Since acidophilus did help to some extent you might want to try another brand; different brands of probiotics have different formulations and one may be more helpful for you than another.

You might also look at your food intake; our ability to tolerate foods can change over time. I, for instance, suffer from remarkably strong cramping if I eat dairy or beans - two substances that I tolerated fine just a few years ago. You might want to eliminate some possible bad actors with regards to food and see what happens; they include dairy (from milk to cheese to ice cream), chocolate, wheat and gluten products. 

You might also want to check out irritable bowel syndrome sites and see what kind of diets they recommend - they can often be very helpful. Good luck!