I have had a sore achilles tendon for several months. Initially, I did very little exercise due to a shoulder injury. That problems has been solved and for the last 5 weeks or so I've been able to walk and run on it but after running today it's very sore. In addition, while my left achilles tendon is the worst right now, the right one started hurting a couple of weeks ago - same symptoms. It hurts when I first get up in the morning, then the pain subsides until I exercise, during which the pain usually lessens significantly. But today, it's staying sore and I'm having trouble walking on it since it doesn't seem to be able to stretch much.