Allergic to Head and Shoulders shampoo?

Ok at first I was using a combination of Head and Shoulders(extra volume, dandruff shampoo) with Pantene 2 in 1 shampoo/conditioner. Recently I started noticing little bumps in my head that itched so I figured it was the Pantene and I stopped using that and just used the Head & Shoulders. But even after a couple of weeks the little bumps are still on my scalp. So I'm assuming it's the Head & Shoulders shampoo. But I have used Pantene before and it didn't give me the bumps, but as soon as I started using Head & Shoulders the itchy bumps on my scalp appeared, plus my slight dandruff is still there. With conditioner I use V05 Apple Blossom, mainly because it smells good lol. So I was wondering if I was allergic to the Head & Shoulders shampoo??? And can someone give me some tips as to what I should do to get rid of the bumps and what shampoo & conditioner to use, my hair is long and thick and doesn't have any dye in it. Thanks (: