Bump on puppy's belly?

My doggy is about 10 weeks old and today I discovered a soft lump on her stomach and it made me worry. I'll take her to the vet tomorrow but I just cannot sleep until I know what it is or if it dangerous. She is a healthy dog, loves to play and runs around the house, eats and drinks water normally and goes to the bathroom normal. I just am scared that it is something incurable.