Possibly overdid it at the weekend running - although have been doing the same distance for past 3 weeks but anyway my heel is so tender to touch. After much googling I think it's Retrocalcaneal bursitis - but not achilles tendonitis (because I really really don't want it to be serious/long lasting rather than any solid evidence!!). I am icing and resting it and so will not run til the weekend but I'm hoping anyone who has had experience of this can tell me their stories and how long it lasted, etc.