Injured my thigh/buttock sprinting a month ago after a hard workout.fine two days later but now dull pain is back in both. hope its not discs nor sciatica. i do yoga and stretch often. pain isnt bad; just when i stretch, tho also sometimes walking ?

Muscle strain: Good that you do Yoga . However whenever there is excessive strain on muscle there may be ligamentous tear which can continue to cause pain in certain position. May be ia wise idea to get examined by an Orthopedic surgeon. Try to apply Ice before and after Stretching. No it is not Sciatica

Watch and wait: Agree with Dr. Trivedi. It is good that you exercise. You may try over the counter pain relief to see if breaking the cycle of pain helps. If the pain is getting better, you may watch and wait. If it is not improving or gets worse, see a doctor. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex.

Muscle spasm : Probably muscle spasm. Try moist heat and an anti inflammatory. If that doesn't help see a physician and get a definitive diagnosis

You are right: You are right in thinking it could have potentially been a "sciatica" from your back. But even if it is, if you are improving, you could still potentially give it more time to see if it resolves. Sciatica can resolve.