Welcome to the forum.
From your description, it seems that you are having inflammation of your arm. Exact diagnosis can be made only after proper examination by an orthopaedician. So I suggest you to consult one.
In the meanwhile, for symptomatic relief:
1. Give enough rest to your arms. Do not raise your arms over your head.
2. Take mild pain killers like acetaminophen
3. Stronger prescription NSAIDS with muscle relaxants may help if simple analgesics do not help.
4. Hot compresses will be useful pain relieving measure. You may apply a local analgesic gel on that area.
I hope this information has been both informative and helpful for you.
You can consult me again directly through my profile http://www.healthcaremagic.com/doctors/dr-saurabh-gupta/64132
Dr Saurabh Gupta.