Hey bro, I have not used Biomex, but was just looking at it on the site. Looks to be a water based injection. Steroids in general, are painful injections. The day after you inject, the pain sets in and can last for several days. The longer you have used gear, the more your muscles get used to it, but it never goes away. In fact, I just got back from training legs and had to push through the pain of a bad quad injection from 3 days back. Even when you are used to the shots, you still get a bad one from time to time. Further, if Biomex is water based, it will probably be a much more painful injection, even for those that are used to it. I have to hand it to you though, you're more of a man than me. I don't use much water based gear because of the pain and because of the fact that it needs to be injected EVERY DAY in order to keep stable blood levels. If you're doing 1cc EOD, you should switch to 1/2cc ED. And you should be sure to rotate injection sites. You dont want to mess around with injecting into a muscle that is still sore. 

I get a lot of new guys that want to start using steroids, and for one reason or another, they want to start out using fast acting gear, like test prop. If you've never injected before, these first shots are going to hurt some. If you use something like prop or water based winny, it will probably feel like you got hit with a bat. Logistically, it's just not a wise choice for new guys. If you fall in this catagory, and Biomex is water based, I have a simple sollution for you. Drink it. Water based winny can be consumed orally and will work just fine. And next time, start with a good long acting test as your base, which only needs to be shot 2x wk and if you want to take winny, buy the pills until you have more experience with injecting various sites each week.