I have 1 yr old son &ever since giving birth I've had pelvic pain. Hurts when I sit walk exercise etc. ..Hurts the most when I try to prop my feet up?

Pelvic pain. There is too little information to give an accurate answer. Was the birth vaginal or ceasarean? For example. My guess is that this pain is from the abdominal muscle. You may start with a harmless exercise such as to lie on your belly and lift your shoulder and head as high as possible, hold for a few seconds, and repeat as often as you can. Check with your doctor for other possibilities.
Pelvic boney injury. It could be from chronic inflammation of the pubic symphysis that normally widens during delivery, sacroiliac inflammation or coccydynia (tailbone) strain or nonfused fracture causing pain with the movements described in the question. She should see a physical therapist who specializes in pelvic floor disorders for diagnosis and therapy.
Pelvic pain post par. If you had a difficult delivery, or large infant, you may have disrupted the pelvic fixed joints or l-s spine pelvic joints. Follow up with your OB or family doc.