For you to get adequate help here it will be better if you provide the basic ingredients of your product.
In contribution to others, one suggestion is to use acids naturally associated with your product by so doing it won't affect it's perception much. For example using lactic acid in dairy products. Another suggestion is to use a combination of acids that produce reduced sourness instead of a single acid.
From my little experience I know that increasing the fat content reduces sourness but I can't tell the exact effect it will have on your pH. I don't even know the nature of your product.
Finally, you can search for flavour masking products. Some manufacturers can customize their products to meet your needs, then if you are lucky they may have already existing products that'll fit yours.