I put on a shirt and my pants. Why don’t I put on my shirts and a pant?

I’ve heard that it’s because “pant” refers to the pant leg, and there are two of those, hence the plural. Fair enough. So why don’t we call our shirts “sleeves”?

I could handle putting on my sleeves and my pants. At least that’s consistent.

And there is the added complication when discussing pajamas (I thought of this after posting the previous post): we don’t call them pajama pants. At least we don’t around here. They are called pajama bottoms.

But, darn it if we don’t keep that plural. Pajama bottoms. I can put on my pajama bottoms all day long. But I can’t put on my pajama tops.

English. It’s weird.