Very normal, and eventually it will go away. As mentioned above, can be pain from the surgery itself, the position you were in during OR, and/or the way your body might be compensating with other muscles to minimize discomfort. Keep in mind you are also probably sleeping differently than normally; I am normally a tummy sleeper and I found my nonoperative hip sore after a few days just because I could only sleep on my back or awkwardly on my right side. I agree with heat, keeping Tylenol in you as needed. Keep up the walking, stay hydrated. Stretching didn't necessarily take away my pain but does seem to prevent flare-ups well, I have started stretching daily and it seems to help. Good luck!