As Sera said, switch to a cup/tampon if you can (remember you need different absorbancies for different stages of your period - sounds like it makes sense but I do know girls who use max strength for the whole thing...
)
I was having some trouble when I moved countries as I couldn't find my usual brand of pad and the ones I tried were all causing irritation. Eventually I did find one that caused no irritation at all and have had no problem since (it has a "cotton-feel" cover). It might also be good to switch products between day and night i.e wear a towel at night and tampon during the day.
I was nervous flying solo with a tampon during the day for the first few times, so I used a liner as well for peace of mind.
Also, be sure not to overwash that area with soaps and shower gels while it is sore/irritated. Wear cotton underwear and let the area breathe
