First off, and since no one has said i yet, a first time user should not be taking Anadrol. May as well just go ahead and throw some HGH in there while you are at it. Maybe some insulin as well. Jeezzz... glad you switched to Test alone.
Secondly...
25mg of Anadrol twice a week? WTF? Unless you mean twice a day this is not good advice. You may as well be injecting 50mgs of test twice a week while you're at it. Whats the point except to shut your HPTA down?

Base dose for Abombs is 50mg a day.
The only reason an air bubble is gonna cause pain is if its a big one and it forms a pocket in the muscle and breaks capilaries. Little airbubbles that dont rise to the surface when you flick the syringe arent gonna do you any harm.
Try warming the test under hot water. That'll help. And next time go with less test per ml solution. Thats probably the biggest thing causing your pain. Thats just a lot of test per ml.