Thanks for your question on Healthcare Magic.
I can understand your concern.
In my opinion, you are having internal
soft tissue injury in the shoulder joint which is causing such sever pain on sudden movements like smashing, throwing ball etc.
So better to consult orthopedic doctor and get done
1. Clinical examination of shoulder joint
2.
X ray of affected shoulder joint
3.
MRI of affected shoulder joint.
If it is soft tissue injury like ligament or
meniscus injury then arthroscopic intervention is needed.
If MRI is normal then simple rest and warm water pad application are needed.
So consult orthopedic doctor and discuss all these.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.