There are a few possiblities for the red bumps. Given your previous bikini wax, it may have been a contact irritation (similar to razor burn). It may also have been some ingrown hair that subsequently resolved.
The itching may be due to a condition called seborrheic dermatitis or may simply be a reaction of your skin to the changing levels of hormones during your cycle. I'm not sure what to recommend to help this. You may want to try using a very mild soap such as Dove.