Straight line of bumps?

It could be bedbug bites. Maybe you slept at a friend's house or something and got them? They tend to bite in straight lines, and depending upon your skin type, you may not get an itchy or red reaction. Some people don't even get bumps. If you don't think that's it, try putting some vitamin E oil on the bumps and see if they start going away after a week or two.