Although uncomfortable, the muscle pain you describe doesn’t sound serious at all. The symptoms that you describe can be caused by acute muscle inflammation.

You can ask your doctor about taking painkillers like aspirin, ketoprofen, diclofenak etc. You can also seek more information about using a balsam containing either ketoprofen or diklofenak or seek treatment with a licensed massage therapist (LMT).

To educate yourself, you can also identify the affected muscle(s) using an anatomy book or reference online...your strained muscle could be anything from the trapezius to the rhomboideus major/minor. This new information might help you in your treatment when applying a local balsam and when consulting an LMT.