How long have you been at this game? I ask, because a 3-1/2" pump will kick like the proverbial mule, especially compared to a tame shooter like the 1100.
I have three 1100s with 28" barrels, an LT20, a standard 12, and a Magnum with a Steel Shot barrel I had shortened to 28", so you might say I consider that combination practically ideal. But, I still prefer 26" for Skeet, so I have 2 of those barrels, too. I learned to shoot without the benefit of knowing that you have to have longer barrels like they spout today - thank goodness.
What could have happened... did.