For Leg Pain, please follow the below advise : Keep your leg raised while sitting or lying Quadriceps strengthening exercises- Quad Clenches: Lie flat on your back or sit upright on a chair with leg kept horizontally on another surface. Now, tighten the muscle on the front of the thigh by pushing your knee down. You should feel your thigh muscles clench, Hold for 3 secs. Repeat 10 times twice a day. Short Arcs: Lie flat on your back or sit upright with your leg placed horizontally on a flat surface like a chair or bed. Place a rolled up towel under the knee. Pull your toes towards you and clench you thigh muscles. Slowly lift your foot up off the bed until your knee is straight (keep your knee resting on the towel). Hold for 3 secs and slowly lower them on the chair. Repeat 10 times twice a day. Straight Leg Raise: Lie flat on your back. One leg and knee will be straight and other leg should be bent. Pull your toes towards you and tighten/clench the muscle on the front of the thigh, locking your knee straight. Lift your foot up in the air, about 6 inches off the bed. Hold for 3 secs and slowly lower the leg. The knee must remain straight the whole time you are doing this exercise.

Hi, with the information given it is difficult to tell shin splint or stress fracture, what can be adviced is symptomatic  relief

May be both Chances of shin splints are high

All the very best for the cross country race. Coming to your question about stress fracture , well it can be but it has to be cross checked or proven by getting yourself an X-RAY done . Do check the signs and symptoms of same such as > localized pain and swelling , > discoloration of skin to pink/red. , > pain at rest and on press., pain on easy / jay walking . If the pain is there only when you run or brisk walk please consider that as tendon damage due to improper running strategies which you might have used in recent past.