A Week Ago I Walked 1 1/2 Miles From A

A week ago I walked 1 1/2 miles from a auto repair shop to my home dropping my car off. Some two hours latter, I walked the same distance back to repair shop to pick up car. Next morning I wake up with pain in back upper leg. A few days latter on Web Md the suggestion was to take tylenol and use ice or a coldpack. I thought I strained a hamstring muscle. Now I have a swelling around knee area same leg.