What are these lumps on the top side of the wings of military aircraft?
They are fairings for one thing or another that projects above the wing skin.  Part of a gun or ammo feed system, fuel cap, wing fold mechanism, head of a big bolt, whatever.  Usually, components are designed in the original versions of the aircraft to fit within the wing profile, but mods and add-ons later introduce bits that project beyond it, so the easiest thing to do is fair it in with a blister.