Symptoms suggest muscular spasm which may be mechanical or related to PIVD.
Conditions needs evaluation with X-rays or MRI.
You can try:
1. Hot water compression thrice daily for 1 week.
2. Spine extension exercises.
3. Rest for 5 days .
4. Medications like Myoril, Etova MR, Enzomac and Neurokind LC will help.
Next Steps
Share x-rays..
Visit Orthopaedic Surgeon for clinical evaluation and MRI.