We dont take a different line preflop, just because we have a small pair or for that matter, because we have pocket aces. In tournaments we can have a range for open limping from SB and in certain situations from BTN. The latter mostly in situations with high ICM-pressure (bubble or final table) and a stack size around 20BB, where we do not want to set it up for the players in the blinds to jeram on us and force us to fold most of our range.
In all other situations we raise first in. We can however have a range for limping behind other limpers, and that range can then include small pairs. In particular we will very often complete from SB, when someone has limped in front of us, because we are getting an amazing price to see the flop. If there are two limpers in front of us, there is rarely any reason to make an enormous raise with 44 from SB or BB to play a huge pot out of position, when we are mostly trying to flop a set.
With an effective stack size around 20BB small pairs are often a fold, because we dont want to raise them and then call off someone, who jam on us, and they play poorly postflop, if someone just call us. So for instance if we are CO, where we would normally open any pair, with 20BB effective we just fold it and wait for the next hand. When we get even shorter like 15BB (with an ante) or less, we can start to have a range for open jamming, which can then include most pairs depending on our position.