Voltaren Gel
"This medicine is pretty miraculous as far as my joints are concerned. I'm using much less than the 2gram dose - maybe 1/4 to 1/2 a gram on a joint, tops - and having at least 8 hours pain free. It seems no studies were conducted on it's use on shoulders, but it worked decently enough for mine when I pinched a nerve. 

Make sure you read the possible side effects and all the potential negatives, and test on a single area with someone with you for a couple hours just to make sure you're not allergic. It's been problem-free for me, but everyone's body chemistry is different."