Problem is the "........im guessing since the guy before me used on of those sct tunners that locks the pcm"
I would contact tech support:
https://www.sctflash.com/support
Or find out from previous owner exactly what was done to computer.
Obviously he drove it, and you did, before you bought it.
SCT tuners "can" lock computers, but it doesn't automatically do it, and you should still be able to use an OBD2 reader to scan for codes.
Locking prevents other people(tuners) from downloading the tuning parameters used, to copy them or ??.
You can try this:
1. Disconnect the positive & negative battery terminal cables.
2. Wait approximately 30 seconds.
3. Touch the negative and positive cables together for 30 seconds. Keep in mind I said the cables, not the terminals on the battery.
4. Reconnect both terminal cables to their respective locations.
5. Start vehicle.
It certainly reads like something else may be going on here, fast flashing anti-theft light is certainly PATS/PCM issue.
So I would hate to see you throw good money at "not fixing" the problem.
See if you can get more background from previous owner and also contact SCT, to see if this is even a locked PCM issue