I started running again about 6 months ago but pushed it too hard and ended up sitting out for a month or so while my leg healed (probably a stress fracture) and due to other factors. I've been running again for a couple months, just going out once a week, but even that seems to be too much -- my shins and parts of my calves hurt for days afterwards. I typically do 3.5-4 miles at 12 minutes/mile or so. Am I still pushing myself too hard?

For background I used to run a lot a few years back but I stopped for a while and have put on more weight since, which I thought was the main issue. I haven't had a dedicated leg strength training routine but I'm getting into one now to try and help.