I think my upper arm pain may be due to bicep tendonitis, after doing some research. My current 2-week vacation hasn't help the pain, unfortunately. I'm thinking I will change my exercise routine slightly and see if that helps. (My current hypothesis is that that "butterfly" weight exercise machine introduced the problem. I only switched to that machine after I found that my leg pain (sciatica) was less bad than the "rowing machine" weight exercise machine.)