My dads Non-Hodgkins Lymphoma

My dad was diagnosed with Follicular Lymphoma, early this year, which was a huge shock to us all and it was an extremely frightening time what with all the tests, biopsy and then the start of the chemotherapy. I will say, that I was so proud at how my dad handled things as he had a rocky start with the chemo as he had a few problems with the ritoximab but that all sorted itself out. My dad has non-hodgkins, grade 1 and had 6 chemo therapy treatments followed by a one treatment of ritoximab which has been prescribed every 3 months for a year. However shortly after his ritoximab he started to get aches and pains in his muscles and joints followed by lumps appearing in his neck. He went to the consultant and we found that there were also lumps in his groin and under his arms. He has another biopsy booked for tomorrow and a scan is also booked for next week. The doctors are a little baffled as he didnt even have the lumps to start with when he was diagnosed, so its weird that they have suddenly appeared. I am really concerned and wondered if anyone else has been or is in a similiar situation?