As long as you were varying your engine speed from 2000-2500 when you first fired it up, and kept it there until you shut down and didn't do a bunch of idling, your cam will be fine. When you fire it up next time, just run it to 2000-2500 again and you'll be fine. Make sure you have cam break-in supplement added to your oil though.
My buddies and I have been building engines, racing, and swapping cams in cars and motorcycles since the mid 70's. We've had to stop break-in several times for things like an angry psycho neighbor (open headers in town not popular), police (open headers again), overheating (not my car), and an oil leak (not my build).
As long as you shut it down without idling much and you restart with normal cam break-in procedures, you'll be fine. I wouldn't be real comfortable doing it with a solid flat-tappet with .630 lift and springs to match.
I have no idea where all this cam break-in paranoia comes from, especially with a stock profiled cam and matching valve springs. A lobe will not flat because it turned over 300 times between the time you let it idle down and then shut off the engine. Flat tappet cams were used for maybe 100 years before the big three ever even invented roller tappets.
Stop worrying about your timing chain-for now. If you used a straight edge to check it you're probably just psyching yourself out. Check the distributor and if that's good come back to the forum. It'll take 10 minutes.
It's hard to give you advice unless you tell us how you started it, how long you ran it, what rpms, and did it run fine at first and then start running bad, or was it the same the whole time.
I'll PM you my phone number.