As Jock points out, some breads are just not suited for free form rising. The wetter the dough the more likely it is to spread. Ciabatta is the nth case example. It's so wet you get a bread that is 3 times as wide as it is tall. If you post your recipe we will be able to tell if that is the problem.
Another possible culprit is shaping technique. If you don't develop enough surface tension when you shape, you won't have the structure necessary to hold the shape you want. This is something that you will get better at with practice.
SOme bread just need a little help to hold their shape while rising. This help comes in the form of some kind of rising basket, aka banneton. More often than not I shape my non-pan breads and then place them upside down in a banneton. Once they're risen I flip them right side up onto a peel and load them into the oven. THe baskets provide structure which helps 'train' the loaf.
Post your recipe and we'll start form there!
Kyle
