Thanks for the query.
At 11 weeks of pregnancy when the progesterone levels are high and the uterosacral ligaments have been stretched and become lax due to growing pregnancy, it is likely that you may experience mild lower constant backache which is common and normal in pregnancy. This may be associated with increased frequency of urine as well. But if the urine is associated with burning sensation, then the possibility of a urinary tract infection should be ruled out as well with a urine culture.
The back pain can be soothed with hot water bag fomentation thrice a day. No medication is required and even should not be taken in 1st trimester of pregnancy anyways unless absolutely indicated.
I hope I have addressed your concerns.
Wishing you a safe pregnancy,
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