Leg (minus hip) pain

If I'm not in hip pain to get things off to a head, I now feel a pulled-muscle(ish) pain in the thigh (middle bit) of my leg. Now if needs be I'm going to cut out the walking I do and ask for a sit down after 5 minutes, but this is really getting on my body now. I'm weakening with age, and I know it might sound daft, but walking is starting to become my first weakness. I hate walking too much, and if a hip pain isn't anything to go by, a pain in the thigh bit of my leg is another result!