Protective Muscle Spasm (Neck)

Details: I've had a protective muscle spasm around c6/c7/t1 for almost a year now. It happened one night when I woke up and moved my neck and it popped. I had taken a low dose of kava (an herbal muscle relaxant) though I'm not sure it played a significant role. I couldn't move my neck much at all from a strange position for about two days and there was pain. The trapezius on either side has been palpably taught ever since. Decreased ROM still present, most notably <15° right rotation with chin tucked. X-Ray within last week revealed loss of cervical lordotic curve.

Questions: 1. Is it always safe and advisable to attempt to release a protective muscle spasm at the spine? I've seen one or two vague assertions that attempting to release a protective muscle spasm at the spine without knowing the exact cause could potentially be dangerous. 2. Can someone tell me why I shouldn't just apply a topical muscle relaxant to the area? I'm hesitant to guinea pig with my spine. 3. How would any of you go about releasing such a spasm? Who would you refer to? OMT (Osteopathic Manipulative Treatment, as taught by Erik Dalton) is the only I've heard to specifically address the spasm. Any and all ideas and opinions welcome.

Possibly irrelevant: There were already fairly significant muscle imbalances due to less than perfect posture, 100% flat feet, bodybuilding etc. Things have progressed significantly since then including debilitating knee, hip, lumbosacral, shoulder and neck pain. Knee and shoulder pain were present to a lesser degree before the incident. Significant thoracic outlet syndrome present. I am early 20s.