Back pain is the absolute worst. However, it is really comforting that there are so many different ways out there to help you get rid of it. My advice would be to seek professional help as soon as possible. It is a good idea to seek professional help instead of trying to fix things yourself.
Thus, it is bigger in size than a coverlet. Quilt. A quilt is a piece of cloth that is intended to provide warmth to the sleeping person. It is not to be slept over like a bed sheet. However, it remains a bed covering during day time and hence the confusion with a bedspread.
A patchwork quilt is a quilt in which the top layer may consist of pieces of fabric sewn together to form a design. Originally, this was to make full use of left-over scraps of fabric, but now fabric is often bought specially for a specific design. Fabrics are now often sold in quarter meters (or quarter yards in the U.S.).