I have recently started excercising and have just noticed a lump/knot which is located below my calf muscle, It is soft on top but firmer when pressing in.It is pretty good in size. No bruising, no pain unless pressing on it. Slightly warm to touch at most. I have probably been over doing it at the gym. Possibly a pulled muscle? I didnt notice any sudden pain. I have had a lot of calf and lower leg pain, but I have done a lot of treadmill and elliptical.