Based on your answers, some of the most likely causes of your back pain include
degenerative joint disease (also called osteoarthritis)
sciatica
disk disease
polymyalgia rheumatica (PMR)
spinal stenosis
There are many other possibilities, however.
While conservative measures, such as heat, rest, and over-the-counter pain relievers may help, it is a good idea to see your health care provider for evaluation of your back pain.