hi there, you are suffering from UTI which explains the burning sensation while passing urine. The chunky white stuff which you have described could be exudates from vagina if you are a female due to candida infection which is which and curdy, or it could be small plaques or crystals of small uretharal or ureteric stones.Get your urine exam done for microscopy and culture and accordingly your infection can be treated with relevant antibiotics. The crystals or candidiasis
will become evident on microscoic exam of the urine and you can be treated accordingly. Take care.