Stomach aches because of taking Vitamins at night ?

I figured out that my stomach was aching because I was taking my nighttime vitamins right before bed. See, I usually take 5 pills in the morning and 3 at night. In the morning, I take one iron pill, one folic acid pill, one apple cider vinegar pill, one B-12 pill and one Zrytec pill. I usually drink a 12 oz. apple or orange juice and a pack of peanut butter crackers. It doesn't give me any stomach aches, and I know not to take them on an empty stomach. At night I take one iron pill, one allergy multi-symptom pill, and one apple cider vinegar pill. When googling why your stomach aches with vitamins, they did say that taking them on an empty stomach, especially at night will give you stomach aches. However, I NEVER take vitamins on an empty stomach. I actually will eat a little, drink some liquids and then take them in the middle and then eat and drink some more. I think though, I will try and take the multi-allergy pill as soon as a get home to reduce the amount of pills I take at night. I remember I was taking big 'ole horse pill vitamin E pills and they gave me aweful stomach aches. I went down to smaller sizes and the pain disappeared. I think when there is a large mass of vitamins at one time, it can encourage stomach aches, whether you eat or not. So, I don't believe stomach aches are any incentive for me to do the master cleanse. I will say that I do need to do the cleanse, hopefully at the beginning of the summer. We'll see.