While you are flaring almost any food is going to cause pain. If you'd like to give your bowels a true rest, go on a completely liquid diet for a few days. You may be hungry but you will feel better. Some health care programs recommend this as an alternative to steroids to induce remission. I'm not sure how long it might take to achieve a remission with a liquid diet, but certainly a few days is not going to hurt you and will undoubtedly give you some relief. Think broth, non-acidic juices, meal-replacement drinks.
Raw vegetables, raw fruit and fiber are problems for Crohn's patients because of inflammation in the small bowel, where digestion really takes place. If you can eat cooked fruits and vegetables that is a good place to start; lactose-free milk or non-dairy milks might be good too once you are past the crisis point. Yogurt is a good, lactose-free source of healthy probiotics, calcium and protein - you might need to avoid the really sweet brands, though. White potatoes and white rice should work alright also, and low-fat animal proteins (chicken, turkey, some fish).
As you continue to improve you will figure out what foods you can add back in.
Lactose and gluten are common culprits in digestive problems. Lactose is easy to deal with, either by avoiding dairy products like milk and soft cheese, or by taking lactase tablets with a meal. Gluten is more complicated, but I've been able to be gluten-free for the last 2.5 months and have been very pleased with the result. When you're in the middle of a flare, though, everything is very complicated and it might be hard to figure out what dietary changes are working or not.