Pain could be bcoz of poor sitting posture. Continuous sitting puts load on your muscle bcoz of which it goes into spasm. Muscle spasm gives you pain. You need to correct your sitting posture & take breaks every 30mins.
Next Steps
Apply ice pack 20mins twice a day. If pains does not subside in one week than consult a nearest Physiotherapist.
Health Tips
Correct your posture, take breaks every 30mins.