+1

This is more important for older sufferers, but if seeking to supplement exercise with walking, make sure of a few things (am a deep-tissue bodyworker):

-- Start slowly. If normally sedentary or have been incapacitated due to an accident (as I was a few years back), take small bites ramping up with walk length, until about 60% effort. Connective tissues are designed to yield to prolonged gentle pressure but resist under short, sharp strain. Keeping muscles relaxed and getting them used to working again before taking real load, is the ideal.

-- If there's lower back pain during this 'shakedown' period, it's most likely excessive tone in sitting muscles, mainly the hams. Sit on the floor against the wall, and place a tennis ball under the thigh. Roll the thigh back and forth over the ball, feeling for the taut hamstrings and how painful the ball is when they're tight. Try to relax the hams (don't push down, let gravity do the work) and roll until the tension begins to fade somewhat. Work the ball from the bone at the pelvis all the way to just before the knee to the sides. This will allow the hams to lengthen, which relaxes the lower back for walking. Do this twice a day at first. Now you can stretch...

-- Use good, comfortable shoes. I like NBs.

-- Continuing at 60% effort, there's fat-burning and weight loss. When comfortable, take short bursts at 70%- 80%, which will gradually build muscle. Use gentle hills, carefully climbing a few flights of stairs, to build the glutes, quads, and hams up. These are large muscles that burn a lot of calories, and more muscle fibers = the less load each individual fiber must bear, so tone overall will be healthier than atrophied muscle. I have a few 80+ yo clients that benefitted from stairsteppers in relieving tight glutes and hams, as these load the muscle through the entire range of motion, like real stairs.

If you still feel pain during a walk, it may be something needing pro help; don't push through pain. Enjoy the walk.