Can Izotek be the cause of muscle pain and arthritis?

According to the Izotek leaflet: "Muscle pain, joint pain and increased serum creatine kinase have been reported in patients taking isotretinoin, especially in those who exercised intense physical exertion. In some cases, this can occur with a potentially life-threatening breakdown of muscle tissue. After several years of isotretinoin use at very high doses, bone changes were observed, including premature overgrowing of epiphyseal cartilage, bone hypertrophy and calcifications in tendons and ligaments." Therefore, the cause of your ailments can be seen in the use of Izotek. If the problem intensifies and prevents you from functioning normally, comfortably - please contact your doctor. You may need to change your treatment. I encourage you to read the leaflet of the drug: https://www.gdziepolek.pl/produkty/38761/izotek-20-mg-kapsulki/ulotka

After 2 months I got knee arthritis and swelling of the bone marrow of both hip bones. And now I'm struggling with these pains, because despite the discontinuation of isotek after 4 months, the pain is still there

Yes, it's definitely izotek! I had swollen knees with unbearable pain!!