Hi don't neglect to get your Dr to get you an MRI or at least CT, I am 42 yo now and quite disabled due to spinal problems. They started at the same age as you an most Drs brushed me off due to being young.
Issues for young people with spinal pain can include a serious condition called Ankylosing Spondylitis (AS). Not to say you have it God forbid, however you can get a blood test called HLA B27 that can indicate this but isnt a definite diagnostic tool but is only positive in around 8% of the population in Caucasians, not sure in other races.
And yes it could be a pinched nerve or disc problem but you need the scans done. Dont bother with xray go for ct or mri. Good luck
It could be a pinched nerve or a pulled muscle. If it persists, you might want to check with a chiropractor. Sometimes they can help a lot with any back pain. Good luck!