Heating it of course will help. 23g suck. They're too small. Try a 21-22g and see how much better it works. It's night and day. I don't know why they make the smaller gauges for IM injection, but I guess the smaller the gauge, the less damage it does to your muscle when you stab it... I don't get the part about getting 5cc's of air and having to squirt back in... You shouldn't be sucking much air in other than air bubbles, which you can tap out later. The only way I think you could do this is to have the needle stuck so far inside the vial that the tip extends past the juice. I think you'll get the hang of it, and you'll never wonder or think about this again...