Hello & Welcome to Just Answer,
Having gone through your descriptions, no it does not seem to be due to walking wrongly. You need to get yourself checked out for a condition called DVT (deep vein thrombosis).
Having said that, once you check in with your doctor, which you must, then she/ he would also be excluding these further possibilities perhaps, depending on the detailed clinical:
(a) Muscle spasm
(b) Compartment syndrome
(d) Rhabdomyolysis, etc.
I hope that this information helps. Best wishes. Please feel free to enquire if you have any remaining concerns/ doubts, as it shall be a privilege and a pleasure to try and help as much as I can.