Hello, if you have severe pain
you can use painkillers(nonsteroidal anti-inflammatory medicine), like diclofenalk 50 mg in tablets 3 times per day after meal (only if you have not allergy
for medications and no problems with your stomach, like ulcer). If it is moderate or mild pain you can use same painkillers, but in gel.
Try to keep you arm in one position. Ussualy like your pain could be after some strike or contusion
In the future, if the pain will persist, you need to do x-ray and some blood checking (rheumatological screening).