Shoulder pain

First of all thanks to everyone who gave me some advice on how to increase my appetite. I have tried several of those things and am eating more daily. But since my larynectomy I've also been experiencing a lot of pain in my shoulders. My doctor has prescribed a low-dose morphine but that tends to make me very constipated. So I would rather take something different or a non-opioid. I have tried ibuprofen which looks OK but my doctor does not want me to take too much of that since it can mask a fever. Was just wondering if anyone else has experienced this or have some good tips on things to alleviate the pain. Thank you