Sharp throbbing pain in upper right arm for weeks and getting worse. now it is affecting my sleep. what can it be?

Right handed?: If you are right handed and have been using your arms and hands a lot you could be experiencing pain from aberrant compression at the level of the cervical spine, the brachial plexus, thoracic outlet. These are a few of the myraid possibilities including vascular, infectious, musculoskeletal or inflammatory conditions. Bottom line is you need an exam.