Why does it feel like i'm having sex for the first time it's so tight?

Perhaps dryness: Pain during sex is most often caused by a shortage of proper lubrication. The body secretes natural lubricants during foreplay, and extending/improving foreplay can help this. Using water-based lubricants though is an easy and very effective solution to improve sexual function/pleasure and minimize discomfort. You'll find it over-the-counter at any decent drug store or supermarket.