I feel constant pressure and ache on my back unless i pop it, which i do multiple times a day. is something wrong?

Could be spasm: Most of my patients who feel the need to "pop" their back or neck have mild muscle aching and a good deal of anxiety. It's usually a bad habit, like cracking your knuckles. I recommend bob anderson's book "stretching" to show you a better way to relieve the spasm. Exercise: walking 2-3 miles a day often relieves back pain. If either of these make you feel worse or doesn't help, see a physician.

No it is muscular: This is ok and you are doing your own spinal manipulation like cracking your knuckles. You are most likely "cracking" your facet joints (the small joints of the spine-2 at each levrl) which stretches their joint coverings or capsules which causes a reflex relaxation of the surrounding back muscles giving you relief. There is no harm in you doing this.