I like walking, too, and they say it exercises every muscle in the body. You can do it practically anywhere, which means I can do mallwalking even on yucky days - I'm one of the strange ones who actually always LIKED to exercise. Loved yoga, hope to get back to it. But I understand your fear...just start where you are and increase a little at a time, and don't give up completely. If you push yourself too hard, you'll just have to cut back anyway because of the pain.
Diagnosed: Fibromyalgia, possible Meniere's, elevated liver enzymes, skin grafting on back, arthritis, scoliosis, lumbar disc damage, sciatica, IBS, migraine headaches, tachycardia, skin cancer surgeries on face
Meds: Nortriptyline, Clonazepam, Darvocet as needed
Multivitamins, l-lysine, probiotics, magnesium, malic acid, calcium + vit. D, vit. C
Be yourself. Everyone else is already taken.