I recently changed my second fiber pill of the day to an hour before dinner, and noticed that I was getting bad crampy pain, doubled over kind, before the first morning bm, and then it went away. This went on for a few days and then I switched my fiber pill back to the evening and noticed that the pain did not occur. What causes this? I am so bloated all the time and feel like I am fibered out. I drink over 2 litres of water per day, but eat a lot of wheat floured ingrediants such as cookies, squares, toast. I eat my dinner, usually a big meal, and then I am so bloated from all this. Maybe I need to eat more fruits and vegys? I am constantly experimenting to see what works best. My system usually has 3 bm's by noon, two hours apart. When I don't have the second bm on time, can you believe that I get anxiety over it? I tell myself, my system is not ready to expel it yet, I can't afford to strain. But eating all this fiber, it feels like it is just sitting in the rectum, but as the day goes on, it gets harder, not soft stools such as the morning. I've noticed this question on some posts and wondering can anybody respond as to why the stools get harder as the day goes on?
In a way you have answered your own question. You said that you eat a lot of wheat products? Well this could very well be causing your problems, as a lot of people have intolerances to wheat products that can give them belly pain with excess bloating and gas. Try cutting these kinds of products out of your diet for a little time. Cookies could also be causing problems too. There are plenty of other alternatives for you to try.
Also, if you eat a large meal, as you said that you do at one sitting and in the evening, it is not really surprising that your belly feels very bloated. You need to eat little and often, so six small meals a day and better than 3 large ones. By eating larger meals, you will also feel tired and this also encourages your body to produce more insulin as a result to deal with the glucose and you can get wide fluctuations in blood sugar throughout the day, which is not good either.
So, try cutting out the cookies and wheat products and eating several smaller meals throughout the day rather than larger ones. This will take the pressure off your GI system generally, which does not need to take so long in digesting food and you should feel better.
Also, stop worrying about having BM's. When your body is ready to expel then it will. Be more relaxed about it generally and you will also get on better.
You could also consider taking Acidophilus to counteract the gas by topping up your good gut bacteria. This can also help with gas and bloating.
Pain in abdomen before first bm 
