Originally Posted by Kayty
Also remember that your position on the horse can give you aches and pains. If you are sitting even slightly crooked, or maybe have one muscle slightly tense where it shouldn't be, you can get aches and pains like you're describing. Talk to your instructor about your position and where you are getting sore and see if they think the two may be linked.
I agree with this. If I don't watch it with the manner in which I position my legs, my knees will start to act up. It's very important to keep your leg under you... and make sure your stirrups are the correct length. At one point I was having some discomfort and my instructor told me to lengthen the leathers by another hole. It doesn't seem like very much, but boy did it make a world of difference!