SB Lexus

I have a 2000 RX 300 with 117,000 miles and the ignition cylinder won’t turn, the car thinks the key is still in the ignition so I had to pull the battery cable, do you believe this is a ignition cylinder problem or the cast metal rod I have been reading about in other postings? If it’s just the ignition cylinder that went bad is this a difficult repair for a person with average mechanical ability?