Without seeing the two of you working, it's hard to say what's going on since there are a number of reasons for her behavior aside from laziness. Which rarely is the case when it comes to horses who aren't responsive. There's almost always a valid reason for their (change of) behaviour. The trick is to find it!
.
She could be uncomfortable from ill-fitting tack, or from something a chiropractor or physio needs to sort out.
Maybe you could give her a check up?
.
It could also be the way you ride her, for which you need a good trainer to come and watch and help you.
.
As for the popping shoulder - assuming you are riding English style - I would try riding a lot more with your outer leg (all the way up to the thigh)and support with the outer rein (no pulling!) to keep her in frame. Just pulling the inner rein will create the very problem you get with the shoulder and neck.
.
Other tips; Sit straight over the middle of your saddle. Relax your hips and *feel* the gait so you don't communicate tension through her back and lock her up. Just like when you lead the horse need to swing its hind legs under her to step in front of the track they make with their front feet. (See the lesson on leading with Budainarush and the little arab!)
.
Hope you keep us posted on any progress!

Hi - as Kicki says, without seeing the two of you in action it's hard to see where the problem might be. Perhaps get someone to video you and play it back to see if you can spot any points of tension or whether you are doing something incorrectly without realising it? Alternatively, as Kicki suggests, could you get a good instructor to come and assess you and give you some pointers?
One thing I found really helpful from an instructor I had years ago was to try and ride with my eyes closed for like 10 seconds at a time. Obviously you can only do this in a safe area like a manege, but it really makes you sit up straight and centre yourself on the horse's back as you have to use feel rather than your eyes. I always do this when I feel that maybe I am getting a bit sloppy with my riding or if something isn't working as it should. Finally, I agree with Kicki that it's possible the horse could be feeling a bit uncomfortable in her tack or her back, a check up would not go amiss just to be on the safe side. Either way, there is usually a good reason why a horse does not want to go forward - you can usually only find out what the problem is by a process of elimination and some good training.

I find it strange that the horse is doing well groundwork. Maybe it could be helpful working in two, one person in the saddle and the other on the ground.
Rudi

I will try the eyes closed, that sounds good. :)
I have noticed a improvement on the days we ride bareback, which are days when I do not have enough time to train much, so we just fool around a bit.
I have checked and re-checked the saddle, and it seems to fit well to me, but maybe a more cushioning saddle pad could help?

Definatly, I need to relax more. That's one of the things I always have trouble with. Saturday when I go see her again, I will try the non-costly suggestions Kicki.
:)

Good luck, Nadine! :)
From all what you say, it definitely sounds like a saddle problem to me. It could be squeezing or pinching her when you sit in it even if it seems to fit well enough.

Hi there - just wondering if you've considered getting a saddle fitting expert to double check the saddle? I recently did a Monty Roberts approved course and we had a lecture on saddles - I was amazed at all the things I never realised - all sorts of things that can be hidden within a saddle that can press on a horses back and cause pain/soreness. Just a thought? Other sugguestions given above sound good too e.g.getting a physio to check your mare.

One other thing I learned on the MR course - overuse of the giddy-up or other form of 'stimulation' can end up simply desensitizing your horse or making it become resentful.

I hope this helps and good luck with your mare - it does sound like she has a reason for her change in behaviour.

Sounds a little like my Nicky who is now 19 years old. Six weeks ago she was really lethargic and lazy at or rally which was very unlike her as she is usually quite sparky. We stopped after the first hour session as I was so worried about her. I also noticed that she was eating her food very slowly and losing weight so I wormed her and took her to the vet to get checked over and have her teeth done. After that I increased her intake of protein - more lucerne hay, corn oil and minerals in her feed etc. Last Saturday was rally day again and Nicky was almost uncontrollable - very sparky! Soo.... maybe diet? teeth? worms?

Today she was very hyper today! I tried everything Kicki said, and it worked! :) Rode bareback, and I tried not to hang on her head of get obsessed about her frame. I relaxed, and tried to give her some slack. She actually was bucking, but I think it was a half-spook, because she only got squirrelly in this one corner where there is a shed(and she can't see around it), BUT, she was not lazy or miserable, in fact, she was quite the opposite. We will see how she is doing tomorrow.

Good news Nadine!

Happy to hear that you had some success!