What Causes Foot And Ankles Pain Along With Numbness Sensation?

Hello, I work a desk job 12-14 hours a day. I have daily foot and ankle, sometimes calf edema. I have a numb sensation in my feet when they get very edematous. I have difficulty getting up from a chair and difficulty ascending stairs. I do occasionally have to splint when having a bowel movement. My knee periodically gives out, and I have fallen on numerous occasions in the last few years. When I was in high school, I could leg press over 500 pounds, so the weakness in the legs is profound. I did have a large rash on my arm for a year many years ago that may have followed a tick bite. Could my leg symptoms be from Lyme?