Recently I have notice a small painful spot inside my vagina.there is no discharge no foul smell.it hurts when I sit and I feel a little pressure when I use the bathroom.any ideas

Many ideas, from a simple pimple to a small cyst (around water, pus, or an ingrown hair) to a STD. Look at it with a mirror and a light and report back what it looks like, and rule out STD or not.