My left lower back (little close to bottom of spine) as sworeness and kindly fell like knot. it not really painful just annoying. i been having this for a month and start to bend down. can be from fiber before that i ate lot of it. and cause heartp?

Question not clear: What a young man eats will not immmediately affect his left lower back. There are normal symmetric bumps in that area but if the bump is not the same on both sides it is not normal. Most common is a fatty tumor which is harmless but would not be sore. A painful lump of the spine may be a spondylolisthesis or several different causes. If it hurts, see a doctor.