Hello dear,
Since the symptoms in your 18 yr old started during workout, it can be attributed to musculoskeletal injury.
X ray & MRI of the affected part will be helpful in clinching the diagnosis.
However, other causes for the symptoms need to be ruled out, such as:
1. Nerve compression due to incorrect posture.
2.
Peripheral neuropathy.
3. Inadequate hydration & nutrition status.
4. Deficiency of certain nutrients like Iron, Vitamin B 12, Calcium,
Magnesium, etc.
Symptomatic relief from pain can be obtained with application of analgesic+
muscle relaxant gel.
Nervigenic agents (like Vit B6, B12,
Folic acid) as well as
multivitamin & mineral supplementation needs to be added in the diet.
Meanwhile, he should maintain adequate hydration, take a healthy balanced diet & avoid stress.
Wishing him a good health.
Take care.