Running

I hate wearing sports bras when I'm running because of the tightness around my chest. I'm starting to get used to running without a bra, but what I'm having trouble with is understanding what the long term impacts are?

The internet tells me it's fine, and but it also says that it's a bad idea, which is entirely unhelpful!

Has anyone had experience running without a bra and if so, how did you find it (assuming you have boobs)?