Thank you for your answer. My dad had promissed me, he will talk with his doctor next Monday when he has an appointment and next chemo infusion. He always had back pain problems due to skiing accident 30 years ago and it was confusing him always. He also lost one kidney 5 years ago and he had experienced similar back pain. Again confusing.
But this time it is very strange that the pain is connected with chemo break and it became very strong after few days of begginning with new chemo cycles. He told me that if he is not moving, the pain is not present or at least it is not very strong.
I wish you strong will, faith and luck!
Mojca