4th july, i had sex, few days after period. condom didnt break. 11th had vagina pain! pregnancy strip on 8th was negative! any chance of pregnancy?

Yes: There is always a chance of pregnancy if you are having sex, unless you've had a permanent procedure done to prevent pregnancy such as a tubal ligation or a vasectomy. Your condom didn't break, so that decreases your risk. You need to wait to see if you miss your menses. IF so, do a pregnancy test then. A pregnancy test done before missing your menses may not be accurate.