Even babies that have the tongue-tie ie. their tongues are too attached with a too-long frenulum can learn to latch and breastfeed properly. You would need to talk and meet with a lactation consultation at the hospital so that they can teach you and your son. That could help you avoid getting the frenulum (that little piece of skin under the tongue) snipped before he's older.
If you go through with it, you can ask them to numb it before they do it. It's a very fast procedure and they may not even need to stitch it. If they do, it would be one stitch that's dissolvable. They heal very quickly. You should ask about pain management for him. I won't tell that you it won't hurt him, but it won't hurt for long. It will also be easier to do it sooner, do it now, than to wait until he's older and it gives him speech problems and other problems. My brother had to have it done when he was around 6 or 7 and he still remembers it as being painful... plus since he was bigger there was more blood and more stitches and my mom had a harder time comforting him.
Anyway... you can give him both breastmilk and formula. People call that "supplementing" but even a nursing baby that has the tongue-tie should be able to get enough breastmilk. Watch his diapers for wetness and watch him for weight gain. If you do supplement with formula you risk reducing your breastmilk supply.
If you're able to pump your breastmilk, he can take that into a bottle. See if your hospital will rent you one.