Hi can missing all back molars of teeth cause digestive problems I chew them swallow?

Absolutely. . Absolutely. Chewing is the first step in digestion. If the food is not broken down into smaller pieces and mixed with saliva then the stomach has more work to do. This means that more stomach acid is produced to break down the food. This can cause ulcers and continued stomach pains.
Possibly. If you cannot chew your food well, you certainly can have digestive issues. Also, if chewing is difficult, we tend to avoid fibrous foods. Fiber helps to move the food through the GI tract. This does not mean that this is definitely your problem, but you may want to try a fiber supplement such as metamucil and see if the problem quickly improves, if it doesn't, see a physician!