severe weird back pain?

[heather]

this pain started about 3 or 4 days ago.. it's like my muscles tense up and then from my waist all the way up to probably my middle back i get an agonizing stabbing sharp pain. it last for several seconds and then quites..sometimes i get another pain rite away and sometimes its not for a few hours...please give me some advice because i already had several medical problems this year and im not looking forward to going back to doctors again