Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 75; Flight Crew Total 536; Flight Crew Type 361
Human-Machine Interface; Distraction; Communication Breakdown; Situational Awareness; Time Pressure
Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
Flight Crew Took Evasive Action
Human Factors; Procedure
ZZZ; taxied from FBO to runway XX (announced movements on CTAF). Holding short of runway XX; switched to Center frequency. Third leg of the day; from ZZZ1 to ZZZ2 (via ZZZ3; ZZZ). Called Center to pick up IFR clearance. Center told me to standby. No word back after 3-4 min; so I called Center again. Once again told to standby. OAT was around 97 degrees; engine idling and oil temps starting to climb (a distraction/concern). Center finally called back (around 8-9 min from initial call) and gave a quick clearance - as filed; code; released and call again airborne. I read back the clearance. Typical chain of events; with hot weather; delays getting clearance; idling for a long time at the runway... So once released I taxied across the hold short line without calling again on CTAF. I checked final; and then the runway and noticed another plane on the runway at the other end (business jet; lights on).  I immediately did a 180 and exited the runway - the plane at the other end was apparently already on the roll and departed well above us. Runway is 5;950 ft; so we were never very close...but clearly could have been a problem had I continued my takeoff roll.When I was on with Center; I was not simultaneously monitoring the CTAF frequency - so I never heard the other plane announce their departure. I also didn't switch back to CTAF and announce after being released so they didn't have any indication I was taking the runway. I should have been monitoring CTAF the entire time; and of course announced my intentions before moving.Factors include: multiple delays reaching Center; rising engine temps and concern about timing with Center; last of three long legs that day (one leg with weather over the Rockies); single-pilot (one non-pilot passenger); and probably allowing communications with Center to feel like a tower situation (release treated as takeoff clearance). Winds light. We had landed runway XX on the way in (as had other planes) - so wasn't expecting a plane to depart from the other end (but probably fit their direction of flight).Probably wouldn't have happened if I had departed VFR and picked up clearance in the air (stayed on CTAF on the ground); but I knew Center was reachable on the ground and figured I should just get clearance first. Should have monitored CTAF at the same time for situational awareness.
Pilot reported taxiing onto the active runway without announcing their intentions on CTAF and observed a business jet on takeoff roll. The Pilot immediately exited the runway; with the jet passing overhead; well above.