Me and my boyfriend are sexually active and we use the pull out method and we were sexually active before my period and I just got.off of my period three days ago and now all of a sudden I'm having bad.pains in my.lower back and I'm spotting.and.it has.a.weard smell

The pull-out method is NOT a reliable birth control. The first sign of pregnancy is a missed period, so you'll have to wait and see if the next period appears. If it doesn't, wait two weeks and do an hpt with first morning's urine. Those "symptoms" you are having may be from worrying you could be pregnant (stress) or a mild infection or who knows what.

Well I haven't been stressing at all and we really aren't worried about getting pregnant because we are both adults and we both work so I'm not stressing by no means lol I've just never experienced pain like this or spotting after my period

Hmmmm, it could be a minor infection, like I said, or maybe you are one of those rare women who gets very early symptoms of pregnancy. Be sure to let us know if there are more of these signs and especially if you find out that you are pregnant.

Ok I will and thanks for being so helpful

Lower back pain can signify, along with a couple of other things, kidney problems. No one can diagnose on the Internet. Only your doctor can know your medical history. I suggest a trip to your doctor to be properly diagnosed.