What causes spasms in the intenstines and nausea bloating and constipation?

Likely IBS. Irritable bowel syndrome (ibs) is a condition associated w/ abdominal discomfort, altered stool pattern, & among others accompanying nausea, bloating, gassiness. Often improved by stooling, ibs is defined by changes in perception of gut distension, motility, sensation. Diet & emotional stress play significant roles here in such patients. Need to rule out first inflammation, ischemia, & infection.
See your doctor. Although random constipation and bloating can happen without anything being wrong, sometimes they are an early sign of pathology in your colon. You should see a physician to see if further workup is necessary based on your age. Constipation itself will cause bloating and cramping. Poor evacuation, especially among women is a major cause of bloating and cramping.