You can get an ultrasound which is the best way to rule out any other issue.
Following approach for the chronic/recurrent urinary tract infection may be helpful (this is a stepwise approach);
1) Estimation of residual urine. This is done by an ultrasound examination. An ultrasound is done with a full bladder. Then you are asked to void and ultrasound is repeated. If there is a residual urine amount of more than 50 ml; that is considered as a significant amount. High residual urine in the bladder will not let the UTI eradicated. In high residual urine following investigations would be done;
a) CMG (cystometrogram); this tells about the bladder muscle and sphincter functions. A problem in these would not let the bladder empty properly and thus the recurrent UTI.
b) Pelvic floor EMG; tells about the pelvic muscle dysfunctions and help in the above.
These will need medications to improve bladder emptying.
2) Medications that alter urinary pH helps in eradicating the recurrent or chronic UTI with the antibiotics.
3) Culture for the mycobacterium; this if grown will need a different kinds of medication regime specifically for the mycobacterium bacteria which do not respond to the antibiotics.
4) Gynecological examination; to see for the major cystocele (bladder prolapse). This also predisposes for the recurrent UTI.
5) If above do no help the other investigation contemplated are;
a) Cystoscopy; camera exam to look for bladder diverticulum or any other abnormality.
b) MR urography (magnetic resonance urography to look for infective nidus elsewhere in the urinary tract).