What Causes Bruise And Pain On Left Calf Muscle?

Hi I am 45, approx 5 ft 3 and a little overweight although dont have accurate weight. I have had cramps over the past few nights - last nights being strong enough to wake me. I did pus a hot water bottle down onto it to get back to sleep. This morning I have noticed 2 or 3 bruises in the area of the cramp but also red skin marks - that may or not be caused by the hot water bottle but are not going down. I was admitted to hospital 3 weeks ago for checks for a possible PE due to my breathing being laboured - but VQ tests came back with it being a very low probability of that. The next test will be an ECG plus I am being referred to a chest consultant. I have had probs with chest since I was victim in a pedestrian v car rta where i suffered contused lungs - var breaks inc L1 vertebra, pelvis front and back - wrist and various ribs. Chest pain continues on left side. My left calf where bruising is and cramps were is a litele tender and feels different to usual - the eis no great painwhen i probe it. I do not usually have cramps in adulthood - although I did as a child due to a hole in th eheart but this was prior to surgery.