I suspect your thighs are working harder to carry you because you may be standing a little less straight with the pain. So instead of your skeleton supporting you, your thigh muscles are.
Do consider eating lots of plant foods (nuts, beans, leaves) and cutting down on salty and calcium rich foods (such as dairy) as this will improve your magnesium intake which will help relax your thigh muscles at the end of the day (do they fidget at night?).
Additionally, please consider rubbing some Arnica Gel into your knees, back and thighs. It will help all three areas of pain.
Our Devils Claw (Atrosan) is licensed for rheumatic and muscular pain too, if you want to take something internally. The effects of Devils Claw are cumulative, so do persist with it as the full benefit will take several weeks to become apparent. It has no medical interactions.