I have a different answer for you. I am a top rated clinical doctor of high percentile rank on the internal medicine board exams from the American Board of medical examiners.
Do NOT home treat this.
The possibilities are extensive and most are potentially very serious
Muscle spasm would be an assumption.
He must have and exam.
Even atypical angina is possible.
No supplement treatments are currently indicated. Without exam and labs, evidence based supplement use is impossible, and guessing can cause more problems, rather than help the situation. For example, if he is hypercalcemic...which is dangerous, adding calcium could be deadly. Or, adding vitamin D.
I am a double board certified US clinical doctor. I am board ceritified in adult clinical medicine, and integrative medicine...we use supplements. You are however, without exam or lab information, or imaging [ultrasound at least]. Do NOT continue trying to manage this on your own, or without the benefit of clinical help.
To be very frank with you, I have seen patients in the past who failed to go to the doctor for such symptoms wind up in the intensive care unit, or worse.
Be safe, err on the side of safety, to not create a dangerous waiting situation at home.
Once you have a diagnosis [we do not diagnose or treat on line here] I will be glad, if you find me in medical by request, to go over integrative medicine, which is EVIDENCE based.
Please click a positive for Dr. Thomas.
Come back as needed.