How do i cure a back injury from tennis?!

How do i cure a back injury from tennis?

hi. I'm a 11th grader that plays tennis daily around 2-3 hours.
im in the high school varsity team, and during the season, i had to sit out because of a back injury. I've also had this problem in 10th grade but i thought i cured it because it went away for couple months.
i went to a doctor/psychiatrist and he cracked my back like 10 times and put heat pack then it went away for a while.

as of now, my family is not too rich and going to the doctor costs a lot of money. what can i do?

in detail, the LOWER part of my back hurts, just above my bottom and either on the left or right side (every other day it hurts on my left and every other day it hurts on my right.)

p.s. i have gotten a slight hint of why this is so.
for those who play tennis, i think its these strings i play with as of now (Pro Hurricane Tour) with my Pure Drive Roddick racket. before my back hurt when i was using these strings, and i didnt use em, but im usin it again. could it be the strings?

My guess is you have a herniated L-5/S-1 disc.

This injury allows enough movement to pinch/irritate the sciatic nerve. The sciatic nerve is the largest/most common nerve damaged in the human body.

The key to my diagnoses is it only hurts on one side at a time.

I recommend you never go to a Chiropractor (you stated Psychiatrist) because with actual disc herniation they usually do more harm than good. I recommend going to either a neurologist or Orthopedic Doctors.

I have had back injuries. surgery, permanent nerve damage, etc. Please feel free to see my profile and e-mail me if you have any specific questions.

GOOD LUCK!