I use the Avonex pen, it is my first and only needle injected medication I have administered myself. I honestly do not know if I could self inject with a real syringe…
The vial of fluid in the pen is pressurised to squirt into the muscle when you press the button, which can be a bit of a shock the first few times, it gets easier though. You have to make sure to do your checks, wash your hands, attatch the needle and ensure it is straight in the pen before attempting to inject, checking the fluid is clear and not contaminated. It’s all common sense stuff really.
It’s worth noting it can still hurt sometimes, the pressure of the fluid being injected and the state of the muscle and locating within the muscle plus the temperature of the fluid compared to your body are all factors. I have injected with the Avonex pen for 54 weeks now, about 6 of those have hurt, maybe 2-3 of those 6 have bled more than usual, possibly due to a surface vein being pierced or the muscle not being fully relaxed caused a pressure bleed as I pull the needle out.
Once, strangely enough this week, I have a lump where I injected, it’s going down but is more sore than usual. I don’t know why I have a lump this time, I did bleed more than usual so perhaps I bruised the leg muscle inside.
Overall though, despite telling you about the bad times, the vast majority of my Avonex injections are 2minutes and it’s done, barely any fuss and I hardly even think about it before it’s done for another week.