Hello! Neck pain can be common and often associated with shoulder and even arm pain. This can be caused by bad posture, trauma, muscle strain, degenerative disorders etc. In your case it can be muscle strain, but the pain should have been more isolated. Since the pain is spread in the arm also, it can be 1. cervical radiculopathy, wich in young ages is caused mostly by disc herniation. Acute disc herniations occur in injuries involving cervical extension, bending, or rotation and axial loading. The lifting of weight might have help the herniation to occur. 2. brachial plexus injury, which can be as well caused by weight sharp movements. You may use acetaminophen or NSAIDs like ibuprofen, aspirin, to ease the pain, meanwhile you should see a neurologist so he can plan MRI of the cervical spinal column. I hope i have been of help .