Welcome to Healthcaremagic.
Thanks for your query.
I Have gone through your query and understand your concern.
I suspect you may have Rotator cuff tendinitis
Due to that fact that during the day, your body leaves your arm to act as a traction in which the shoulder opens up space to allow blood to circulate easily to the tendons.
When you are sleeping at night, your body is usually horizontal and therefore gravity is lost as a traction force, which causes the pain to return.
Rotator cuff tendinitis responds well to many common treatment options. Physiotherapy
remains the best treatment for rotator cuff tendinitis.
Thus i advise you to consult a physiotherapist for proper physical exercise for rotator cuff tendinitis.
Meantime have some Non Steroidal Anti inflammatory drugs like Diclofenac
Hope this helps.
Please reply for further queries.
Wishing you good health.