Hi, cause could be pulmonary congestion, pleuritis, cervical spondylosis leading to myopathy. Try anti inflammatory drugs like ibuprofen,
diclofenac for 6 days along with hot compression. If no relief is seen, get chest and cervical spine X ray done.
Topical counterirritants may be helpful. In case, spondylosis is seen on X ray, additionaly physiotherapy along with pain killers will be helpful.