i don't know what this is- please help

Multiple myeloma (in a nutshell) is a cancer that develops from plasma cells found in the bone marrow and can develop where bone marrow is found (pelvis, spine and ribcage) hence the term "multiple" myeloma because it is often in more than one place.

Normal plasma cells produce various immunoglobulins (Ig's), in response to various types of virus or bacteria. But myeloma cells produce abnormal Ig's

A normal molecule of Ig is made up of two heavy and two light chains. In Chain disease only the heavy chain of the immunoglobulin is produced and is it is usually incomplete. You may also hear it called Heavy Chain Disease. This is very simply explained!

Since I live in the UK, I would think that treatment may vary, so I suggest that you look on the internet. I add a word of caution here... only go to reputable sites because you will find lots of unfounded advice from all sorts of cranks... there's lots of them out there. I made that mistake a few years ago when my husband was diagnosed with myelodysplasia. I frightened myself out of my wits!