Last night I started coughing hard while sitting on the couch.. out of the blue...and I noticed that my hands and lower forearms started burning and aching. Then, it went away. No more coughing and no more pain or burning. I felt fine getting dressed for my hike this morning, but into my uphill walk and for the rest of the walk, I noticed a feeling of constriction in my right forearm near the elbow. I thought something might be too tight. But I didn't have clothing on that was tight in my arm. Then, I noticed a feeling of pain when I flexed my wrist up and down. When I got to a place where I could remover my coat and pull me sleeve up, I looked for a bruise, but there was none... just a knot in my right forearm with extreme tenderness and swelling. The swelling has gone down some and I don't really feel a hard knot there anymore, but the tenderness to the touch is still there and it still hurts in that spot to flex my wrist up and down. It really hurts all the way up and down my forearm when I flex up and down. What could this be? Do I need to see a doctor?