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It might be due to muscular sprain after improper posture during sleeping,sitting,working and weight lifting.
There might be some pressure on any nerve route in between.
Start nsaid with muscle relaxant
Apply nsaid gel locally.
Therapeutic dose of b12,b6,folic acid
,minerals will be helpful.
Intra muscular injections of b12,folic acid is advisable.
Avoid exercise,sports activity,weight lifting till get complete cure.Physiotherapy
Start treatment under guidance of orthopedician.