If you are a weightlifter, you should be using hook grip. End of story. Before I tell you why, I need to tell you something. It hurts. Sometimes it REALLY hurts.
Don’t worry though, your hands WILL get tougher and you WILL get used to it.
Now we have that out in the open we can move on.
What is hook grip? It is simply trapping your thumb under your fingers when gripping the bar rather than the other way around.
As far as the technical reasons for using a hook grip go, there are two main reasons for you to consider, in the very simplest of terms.
The first is the strength of the grip. Using a hook grip will have a mechanical effect on the barbell, namely reverse torque, therefore strengthening your hold on the bar.
Secondly, using a hook grip will mean you keep your arms looser and turn over the bar faster, because there will be far less tension in the muscles that surround the elbow.
I suggest you start introducing it as early as possible in your weightlifting while you are still handling modest weights and you can get used to it. Or at least learn to not moan about it!