Lump above the buttcks on my lower lower back...is this dangerous?cancer?

Possibly: Hard to know unless you get a physical exam by a physician. Most soft tissue masses are benign (not cancerous)- i.e. Lipomas, cysts, etc.. But there are cancerous masses that can occur anywhere. See your physician.

You probably: Need a professional to examine what you are reporting. There can be normal bony findings, but are symmetric right to left, and many innocuous lumps. But rarely, there is something wrong. If between the buttocks, toward the anus, pilonidal cysts are common. Go get checked.