Female chams can become egg bound for several reasons. The most common is not having a good lay bin for her. Female chams can and do produce eggs, infertile, even without the presence of a male. If she is not provided with an adequate lay bin she will hold onto the eggs and become egg bound. If the eggs are not laid, or possibly surgically removed, she will die. If you think your cham may be egg bound, get her a proper lay bin and get her to a good herp vet ASAP.