I have been on birth control pill for 3 years now and all of a sudden i have been spotting off and on all week and having painful burning urination?

Get a check up: This is not normal and you should be examined by a physician. There could be an infection that needs treatment.

Dysuria: Dysuria is the feeling of pain, burning, or discomfort upon urination. Although dysuria frequently indicates the presence of a urinary tract infection (UTI), it can have a variety of causes. Dysuria should always trigger a visit to a health-care professional for evaluation and diagnosis. http://www.emedicinehealth.com/dysuria/article_em.htm#dysuria_overview