I keep feeling this like tapping inside the back of my leg. It s hard to describe, but I will do my best. Feels like a trembling or maybe a pulsating. It s very faint but enough to be noticeable. It comes and goes, but when it s there it taps every few seconds. Then it will be gone for a while. I m not a smoker, but I am morbidly obese. I m not on bed rest or anything like that, but I have been sitting more than typically over the past four or five days. I ve never had an injury on that leg. I m worried it might be something serious like a blood clot or something along those lines. It seems like it comes back when I m bending my leg (when sitting), but if I lie down it seems to stay there. Walking/standing seems to make it go away. I m a male, 34 years old. I took an aspiring for an unrelated headache. It seem to go away for a while but it s back. Not sure if that caused it to go away or if it was something else.