I Have Chronic Pain In My Lower Back And Down

I have chronic pain in my lower back and down both of my legs. I think it is sciatica because the pain radiates down to my big toe on the left leg. Sometimes the pain is worse on the right side or on both legs. I have swelling especially around my left knee. I have to use a can now because I can't move easily or stand too long. this has been going on for a year and got worse a year ago after I got my 2nd blood clot in my right leg. I have been in and out of the E.R. because of the pain and swelling and checked for blood clots a week ago and have none. I am on blood thinners.