Don't do yoga if a Westerner. We don't have the mindset for it.

Back pains might be the result of many different variables, ranging from bad genes, wrong lifestyle, old injury, bones, nerves, muscles, weight, shitty materace, etc, etc.

Try to observe if warm (not hot!) bath with salts/magnesium seems to ease your pains.

I just got back from the Chiropractor, and can attest the effectiveness of a good one if you can find them. There aren't a lot of other nonsurgical quick solutions that aren't just masking the symptoms.

I know you said no doctors, but Chiro's often have same week apts and cost a lot less, especially on first meeting.