Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain severe pain in shoulder along with difficulty in lifting the arm when palm facing up can be due to causes like Frozen shoulder, labrum tear,acromian-clavicular joint separation [AC Joint separation], rotator cuff tear, bursa or tendon impingement.. I would suggest you to consult a trained Orthopedician and get evaluated and he can perform certain movements of your arm and shoulder by carrying out certain tests like Apprehension and relocation tests,drop arm test, AC Joint relocation test etc as per suspected cause and also advise you investigations like MRI Scan, CT Scan, x ray etc to rule out the exact cause of the pain and difficulty in elevating the arm and treat you accordingly.. You can be advised to take anti-inflammatory painkillers, muscle relaxants, steroid injections and also physiotherapy and hot or cool packs depending upon the cause.. Avoiding excessive exertion to the arm can also help.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.