I am sure that you know this already, but the septum is the divider that separates your sinonasal cavities into their respective sides. The fact that it is deviated, just means that it is not perfectly straight. In a perfect world, every persons septum is straight, however truth be told most septum have some degree of deviation to them. The trick then become determining which deviated septum is clinically significant, and which is not. The anterior half of the septum is cartilage, and provides support for the dorsum and tip of the nose. The posterior half of the septum is bone (made up of the vomer and perpendicular plate of the ethmoid). Most of the time it is the anterior cartilaginous septum that is deviated. There is nothing about a septum being deviated that should increase your rate of coming down with a cold to any significant degree. However, the nose is lined with inflammatory/erectile mucosa...if there is a deviated septum, then one side has less room to begin with, so it may obstruct easier (due to allergy, viral infection, etc) and give cold-like symptoms (nasal obstruction) on that side. A septoplasty (fixing a deviated septum) is a very routine ENT surgery
. Cost is not usually prohibitive (pending insurance I am sure), and on the average it is not a super painful surgery (although some pain is obviously expected with surgery). I recommend getting an exam from an ENT and discussing these questions with them. Best of luck.