I have tendonitis in my shoulder; so says my chiropractor. I can't think of anything that may have brought it on, except for maybe repeated casting. But it doesn't hurt when I cast, only when I twist my arm certain ways like when I put it into my shirt sleeve. My typical wade trip is about an hour, three times a week, but every week or two I might be out for 2-3 hours. I use a 5'9" fast action spinning rod. This is my fifth year of this level of fishing, and the first occurrence of this problem. Would a longer, medium action rod reduce stress? A bigger reel diameter? Is it just old age (59)?