Are your plants growing in your garden or did you start them indoors?

It sounds like a mosaic virus. Do the leaves look like this:

I hope that they don't because mosaic viruses have no cure. That pumpkin is a goner if it has any of the mosaic viruses his early in the game. There are several things you can do to control the spread of mosaic virus. You can throw out or burn infected plants, disinfect tools after using them around infected plants and you shouldn't save any seeds from infected plants. There is lots of further information on the internet.

Could you tell me some more about problems you have had growing pumpkins?

If you can, try planting in a completely new part of the garden, or property. There are also some mosaic virus resistant varieties of pumpkin you could try.