I had excruciating pain in my right shoulder and both knees for years. I tried all sorts of pain medications and medical gels with minor temporary relief.
I had heard rumors of mechanics, sports figures and veterinarians using WD40 on their painful knees shoulders and elbows. Well, I had a can kicking around my garage and I went to retrieve it. I sprayed it on my shoulder and knees - I could not believe it but the pain went away within ten minutes. The pain returns after I do physical work and I solve it with the spray and massage it in. The only detriment is the mild odour that a mechanic has to live with but it disappears after I wash the area with soap about an hour after applying.