My Achillies tendon has been slightly tight after runs for almost a month. I took 3 days off for bad weather and a blister on bottom of my foot. Today I was stretching a little to see how it would take it and it acted up pretty quick and it is a little sore now. Before it was only slightly sore for a half hour or so after running when sitting. I'm thinking it's essentially injured, and I don't plan on running for a while. I have a half marathon May 1st; I have my long run up to 10 miles which I did 3 times over 3 weeks, so I imagine I'll be able to complete the run. How worried should I be? How long should I give the Achillies tendon to heal before running? I've heard Achillies tendon injuries are serious