Moshposh, I struggle with this exact issue. My left shoulder and chest are painfully stiff due to lasting side effects from radiation for breast cancer in 2013. In addition, I’m taking Exemesthane, an estrogen blocking drug that causes arthritis and joint stiffness. All my life I was a natural rider with an equitation build for riding hunters and jumpers. Now I have a stiff shoulder and less joint mobility overall, which effects my release when jumping and I look tense even when I’m not.
When my breast cancer progressed to Stage IV in 2015, I decided to spend as much time riding, showing and enjoying my horses as possible. To keep myself strong in the saddle, I do Pilates and I ride without stirrups. Keeping my shoulders soft and fluid remains an ongoing challenge. Surprisingly, there’s not a lot of helpful information about this problem even though it affects all aging riders (I’m 62) to some degree. My trainers have suggested riding with driving reins, riding with one hand while holding the free arm straight out to the side and rotating it in big circles, and rotating both shoulders in big circles at the trot and canter. These exercises help and they create body awareness but for me, they didn’t get to the core of the physical problem.
I finally found a sports based physical therapist who helped me strengthen and stretch my shoulder. She worked with me on a foam roller, with elastic bands and on her red cord system, which involves slings and pullies. I improved so much my trainers stopped mentioning my shoulders in lessons. Then I fell off in mid September and fractured my sacrum (lower back) and had to rest until last week. Now I’m restarting physical therapy for my back and shoulder. If things go well, I’ll start riding again in mid December.
Riding as as an adult is about managing physical and mental issues and doing the best with your body on any given day. Never give up and keep searching until you find a solution.
Good luck, Moshposh!