Back pain. Would be the reason for it?

When I was in 6th STD I was fallen down on my back side on a cement slab due to rain so at that time I can't even take breath for almost 1minute and my friend helped me to stand up I used volni on my back,this was the early story and now these days of my B.Tech iam getting back pain when ever I lift anything and the pain was no t so heavy but it usually had and sometimes without knowingly my back bone will be pained and that I can't even sit, just I need to sleep for five minutes(if I won't do sleep position I may fall down) and it will be done.If I won't rest it was not been possible without rest and these sever pain will occur for a long time like may be once in a year and what would be the reason for it?