Lower abdomen has been hard for 6 months now but i'm not pregnant. feels hard especially when lying down and bulges out. uncomfortable to lay on tummy?

Any surgery: have you have any surgery like C-section or similar lower abdominal surgery? .If you did that will be a hernia if you never had surgery then the hardness in the abdomen could be either female related like a blood or mass in the uterus or large ovarian cyst. or digestive which is the least likely from your description like bloating from IBS either way you need to seek a physician evaluation please.