Boiler wont stay on for very long?

Ok im getting slightly worried that I might have messed up my thermostat. Basically I stupidly screwed a bookshelf to the wall and it was very close to where the thermostat is. The heating now will come on for about 10 minutes or so and then goes off again. I think the boiler isn't that old as the places I am staying in is only about 5 years old. I see the burner light come on when I first start up the boiler then shortly after it goes off again. There is power going to the thermostat still but I am just wondering if this could cause the problem that I am getting. Any help would be much appreciated.