Is it possible to damage a bone from running?

My right femur is very painful and I don't think it's a muscle problem because it doesn't feel like muscle ache, but when I put weight on it, it hurts lots at first then settles into a dull ache. I hate to sound like a hypochondriac but I'm worried it could be caused from a previous leg injury that may have weakened the bone??? I can still run on it but not for long and I tend to limp a bit and it is very hard to start running again if I stop for even a minute. Any idea what it is??