Being aware of basic running mechanical principals may ease some of those aches and pains and definately prevent new ones.
1. Try to keep your head steady. Keep eyes forward… run point -to -point. Your head goes where your eyes go and so does the rest of you. If your head is going from side to side, you will be encouraging forces that pull you off center. Try to relax and keep the head where it belongs: centered between your shoulders.
2. Arms should be maintained at 90 degree angles. Keep your elbows into the sides of your body. This encourages the use of the shoulders for optimal forward force. Lightly keep your thumb and forefinger touching and open your palms now and then. Never clench your fist. If you drive the arm back (not out and back – simply STRAIGHT back at a 90 deg angle), it will simultaneously create an increased stride in the opposing leg. Interesting body mechanics, isn’t it?
3. Foot and Leg: Land on the ball of your feet when doing sprints. The objective of forward motion speed is, as said, drive forward and straight ahead. Pay attention to horizontal motion and stop bobbing up and down.