Can gerd cause moderate nausea from not eating and several hours after eating cause stomach/intestinal spasms and pain (without any sxs of heartburn)?

Possibly IBS: You possibly have a condition called irritable bowel syndrome, but i can't be sure since I do not know how long have you had this. Irritable bowel is a very common illness and occurs more often in female. Gerd typically causes "heartburn" symptoms and you should get some relief with pepcid/tums/prilosec etc.. If these are new symptoms and treatment above don't help, consult doc. Good luck.