I Am 73 Years Old, 5"2", Weight 261. From Youth

i am 73 years old, 5"2", weight 261. From youth to age 58, i weighed 135 pounds. Had a complete hestaray and quit smoking, gain most of my weight to date. I can only walk about 200 steps, and the pain is servere in my neck,back, upper arms, sometimes in my lower back and hips. After I rest about 15 mins, I can then walk another 150 steps, and again have to sit due tothe pain. I am unable to do any house chores due to the pain that will come on. I recently seen a doctor, and was told my fat in my body was causing my nerves to hurt. I have on neck and he said the presser from being fat is compressing my nerves, which causes the pain in my arms and shoulders and neck. I have been walking 200 steps now for 2 months and the pain is not going away. I thought I could work the pain out by trying to walk. Yes, I have one bad knee, but that pain isn't anything like this nerve pain. The doctor said unless I lose 100 pounds, I will probably will have this pain. So, is there any other reason way I hurt so bad in the places I told you about. I requested some pain pills to help curb the pain, and I will be taking celecoxib for now. None of the over the counter drugs seems to help.