Stomach aches

Hi, just wondering that the day after i had intercourse i had an ach in my lower stomach and i was wondering if that means anything has anyone felt this way before?

If the pain lasted just that day and never appeared again, it is nothing to worry about, probably just something transient. If this pain became chronic and started appearing every time you have sex, it is obvious you need an examination.
There are many things that can cause pain after intercourse. It could be different infections, both UTI and STD. It could be cysts on ovaries that would also cause pain around ovulation and periods.
It could be uterine growths like fibroids and myomas, which also cause pain after sex and a range of whole other symptoms.
It could be cervical dysplasia, development of abnormal cells on cervix, the beginning of the uterus.
So, if the pain persists, make sure you see a doctor and have that checked.