Diagnosis ??? "pinched nerve" means someone is guessing but has no clue. Which nerve? Pinched or swollen? Where? How long? What is pinching it? See a reputable neurologist, get EMG and nerve conduction velocity testing. Pinpoint the diagnosis (exact identification of the problem). Treatment may include fixing hypothyroidism, controlling diabetes, removing a cervical disc, carpal tunnel surgery, ulnar release..
Radiculopathy. Radiating arm pain and a feeling of tightness are common symptoms of radiculpathy... Stemming from compression on the nerve root(s) in your neck. It can be due to a disc bulge- or herniation, slight instability or deformity or bone-spur formation and arthritis... Physical therapy with cervical traction can help, including exercises and anti-inflammaroties. Try that for few weeks to see how it goes.