Can you get pregnant having sex 3-4 days after ovulation?

Technically no. Technically, the egg doesn't hang around for 3 days after ovulation; However, the trick is knowing exactly when ovulation occured. This is difficult unless you are getting an ultrsound every day in a fertility clinic. Otherwise there is a lot of variation as to when ovulation occurs. Preventing pregnancy by timing intercourse to avoid the fertile window has a high failure rate. Best wishes!
Fertility. As long as we are talking about the release of the egg from the ovary as your definition of ovulation then no, this is not when pregnancy occurs. Sperm have to be in the vagina prior to ovulation to cause pregnancy.