I have days where I feel more pressure than others. My wife will sometimes tell me she thinks my pants are "squishing" the baby (like, sweatpants.. so they're not actually tight but they're not always positioned below the bump). My theory is that our bodies are NOT that fragile and babies are protected in there. Major impacts, such as a fall or car accident, could be harmful, but if there's no way they could be at risk from pants.
You're right - it's probably a growth spurt. Maybe your bump will have a pop soon!