is my boiler overheating?

I have no experience with boiler, I touched the flue duct on the top of the boiler,
it's hurt, very very hot, I think it's over 100 Celsius (°C), is this normal?
also the top of the boiler is quiet hot, about 65 Celsius (°C).

the problem history:
1. my boiler had a problem when I had a show, hot water stopped, flashing quickly, I reset it working again.
2. next day reset sometime working sometime not, asked a plumber checked, he had no confidence, said might be PCB, but he said I might pay for nothing, so we stuck there
3, After 2 days, the boiler stop working completely, no CH no HW, flash every second, reset no help. the fuse broken, replace still broke again, at last I found the overheating short 2 wires(red one green one） which are for overheat thermostat and water pressure switch and air pressure switch, I fix the broken wires, then the fuse no longer broke, but boiler still not working
4. replaced a PCB, flashing quicking, checked fan is working, short the air pressure switch, then I can hear spark, but no ignite, not working, linked out the water pressure switch, WOW, Ignite! fire up, :lol:
5. I am trying to check if the boiler is overheating or not...