Sorry to hear about the crashes and thank you for the report link.

That particular report is actually when Firefox fails to shut down within a certain time after you exit out of it -- it crashes itself. This shouldn't cause any problems in normal browsing, but it is annoying nonetheless if you tend to close Firefox several times during the day. As a short-term workaround, try keeping at least one Firefox window open until you are completely done with the browser.

Is that the situation you're seeing, or is the crash occurring while you're actively browsing? In that case, do you have any other report IDs you can share? Please check the support article "Firefox crashes - asking for support" for steps to get those crash report IDs from the about:crashes page, or from disk if necessary, and then post some more of the recent ones here.

Of course, now that I read your post more carefully, I see the real problem is Firefox freezing. There's no report for that. Does anything in this article help: Firefox hangs or is not responding - How to fix?

In the bug report, someone suspects an add-on is the issue.

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?