Shadow-Lord's page

Pathfinder does have some stuff for play beyond level 20. You can find it in the PRD at the end of the Gamemastering section.

You can't take the same class again. That isn't stated there, but it is the rule already. You can't be a Sorcerer 20/Sorcerer 1. However, if you go Sorcerer 21 instead, your caster level does increase to 21 and you can gain additional spell slots (as detailed above).

Base Attack Bonus increases as normal. However, you are limited to a maximum of 4 attacks from it.

So it would be the third one (+40/+35/+30/+25)?

I understand the pros and cons of multiclassing early, but I don't understand it regarding a character that has reached level 20 in one class and decides to continue playing their character with a different class.
There is also the question as to if you need to select a different class or can you go into it again? EX: Level 20 Sorcerer wants to go into Sorcerer again.
Would the caster level increase to 21 or would it just stay 20?
Base Attack Bonuses increase how?
Would a Fighter's DR stack with the second Fighter's DR?
Can you gain more attacks per round? Ex: level 20 Fighter and level 20 Gunslinger would be? +40/+30/+20/+10 or +40/+35/+30/+25/+20/+15/+10/+5 or +40/+35/+30/+25?
This does not need to be answered quickly, but an answer to each would be greatly appreciated.

Let's say there is a level 22 character. Inquisitor 20/Cleric 2. Would their Caster Level be 22 or not? Would Magical Knack Trait help? If so, what would be their Caster Level. Me and my friends are playing a very long campaign where we multiclass after level 20. Also, how would they go about Domains? There are plans to multiclass into Saint afterwards.

No, you don't need to know Lesser Restoration or Restoration to learn Greater Restoration. But since Greater Restoration is highly expensive to cast and you have to wait a long time to get it in the first place, it is to your benefit to get Restoration if you can. To a lesser extent, this is also true of Restoration compared to Lesser Restoration.

Thank you very much. I will inform my friends.

Must you know Lesser Restoration or Restoration to be able to learn Greater Restoration? Possibly something similar for a Sorcerer. I have a friend who's playing Sorcerer and wants to know so that they doesn't want to waste their time getting lower versions of a spell when the spell they really want is the greater version. Again, is it a necessary to to learn a lesser/normal version to learn a greater version?

Can a normal character get mythic feats? Example: I am Fighter and i have Vital Strike, after going up in level I want to get Vital Strike Mythic. What would I have to do to get that feat?