Hi, I’m sorry that no one has felt able to answer your query, and that you’ve had to find our site.
We are patients rather than doctors so can’t give you medical opinion. while some of your symptoms could feasibly be myeloma, eg fatigue & back pain, & some of us did have less common for myeloma symptoms at diagnosis, I don’t think I’ve met anyone who had grinding knee pain, myeloma usually affects the trunk and/or long bones. The problem for people presenting with myeloma is that many of our symptoms such as tiredness, back pain, repeated infections, could be due to a number of conditions.
It is always terrifying to find information on the internet, especially about cancer, when you only have a few test results to go on so you are left with more questions than answers. I hope your Dr is soon able to reassure you. If not, the next test is electrophoresis, a blood test to check whether you have monoclonal proteins known as “m spike” ( which by definition are cancerous). The only absolutely conclusive test however is a bone marrow biopsy to allow microscopic analysis of the plasma cells in the bone marrow.
I really hope none of this proves necessary for you.