To begin, what type of pain is it that you are noticing? Does it feel like muscle spasms, or tenderness in your arms, or another type of pain altogether? Does this get worse throughout the day or does it not matter what time you practice? Does stretching help this pain if you do so before practice? Do you have any other problems with muscle weakness or spasm if you do aerobic exercises such as running or weight lifting?
These are important questions to consider and discuss with your primary care doctor
as the answers to these questions, along with your medical history and presenting symptoms and clinical exam will best help him or her decide upon the appropriate treatment options. This may include lab tests or a referral to a specialist depending on what is found. In general, it is very likely that you are experiencing cramping from muscle deconditioning and stretching and forearm exercises will help improve the symptoms that you are experiencing.
On the other hand, there are other diagnoses that are very concerning and so it is important that you are evaluated by your primary care doctor for further evaluation and work up for these symptoms.