It feels like your muscles are rupturing... are your joints stiff and painful? These can be symptoms of a rheumatic disease. What is rheumatism? Rheumatism is caused by a disturbance of the immune system, i.e. the body attacks its own structures such as the inner skin of the body. The causes of such malfunctions of the immune system are still unknown. It is known that about two percent of the adult population suffer from rheumatic diseases.
https://www.healthtv.de/c_eur/de/blog/gesundtv/rheuma-bei-erwachsenen
Watch the film sequence (see above) - Dr. Ahmadi explains the disease "rheumatism" as an experienced doctor.