Tell me, they are useless at the moment
Only use it in head ons and within 5km, it can bonk maneuvering enemies in the face
Make sure you know how to use the Viggen’s very good radar, and like the other person said only use them in short-range headons. Never use them if the enemy is looks like they can defend (multipathing or notching). Also, since it’s a Sparrow, a very rare and intelligent opponent is able to barrel roll them depending on their aircraft. My usual way of playing the JA37C is to full afterburn at low altitude towards your own base - you’re usually the first there - and to collect your two free kills against zombers. From there you can either rat around with your sidewinders, or just RTB to get some more Skyflashes. Even as a bad player, I have a 62% WR and a 2.3 KD.
If you want, you can post some videos of what you’re struggling with.