This is likely to be myofascial pain syndromes. Muscles of this area can develop myofascial trigger points. These are hyperirritable tender spots in palpable tense bands of skeletal muscle that refer pain. This can be associated with workouts with the weight. Trigger points may develop after an initial injury to muscle fibers. This injury may be a noticeable traumatic event or repetitive microtrauma to the muscles. The trigger point causes pain and stress in the muscle or muscle fiber. The treatment is following;
1) passive stretching of the affected muscle after application of sprayed vapocoolant.
2) physical therapy; simple muscle stretch, augmented muscle stretch, post-isometric relaxation.
3) deep electrotherapy; iontophoresis, phonophoresis, short wave diathermy, electrical stimulation, high voltage galvanic stimulation, biofeedback.
4) local analgesic patch / ointment / spray
5) anti-inflammatory analgesics; Ibuprofen (Motrin / Advil)
6) ischemic compression therapy; pressure on the points
Your may consider an EKG to rule out any cardiac issue (rarely associated), just for the cautionary reasons.
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.