I have lower backpain which started a couple of months back but is becoming more constant but it's more painful at night and wakes me up and to change position really hurts. i don't have periods but have had spotting, swollen underarms?

Evaluation needed: If you no longer have periods & now have vaginal spotting plus back pain you definitely need to be evaluated & examined by a GYN provider, to check for fibroids, tumors, infections, uterine hyperplasia (& possibly an unusual pregnancy depending on your age) A history & physical exam plus an ultrasound of the pelvis would be very helpful, in addition to some basic blood work

Doctor can examine: Some causes of lower back pain include: back muscle strain, back ligament sprain, fractured vertebra (spondylolysis), slipped vertebra (spondylolisthesis), herniated disc, spinal stenosis, spinal arthritis, urine infection, kidney infection or stone; tumor in the spine, kidney, or elsewhere; fibromyalgia, etc... With such a long list of possibilities, one's doctor can examine.