Hello and Welcome to HCM,
Thanks for writing to us.
The pain your son experienced seems to be due to a muscular pain
most likely caused by a heavy exercise and weight lifting. Taking mild pain killers and muscle relaxants will bring a short term relief. A physical examination is necessary to find out the exact cause.
Meanwhile you can do a hot fomentation and apply a local analgesic
gel on the area to relieve the spasm.
Hope this helps you.
Wishing you good health...
Dr Saurabh Gupta.