1) U might be lifting more than your body allows (which might explain ur injury).Thus sacrificing proper form and ROM. I used to train heavy, i noticed that it focus more on explosive burst of strength instead of muscle contraction. People tend to rush the set as the weight is heavy, thus focusing most strength at the beginning of the ROM. If u want a dose of soreness addiction every single session, try to finish the rep slower with a constant ROM speed to get more muscle contraction.

2) DL and overhead press alone does not work the bicep directly. Most bicep is only use as a balancing muscle for these 2 exercises. I read somewhere that states for every 2kgs gained, arm size will only increase by 1/2 inch if trained properly.

3)Doing DL once a week is more than enough to kill my back. Twice a week with max weight and x number of sets? NO thank you.If u want to gain weight and mass, i suggest u go for full body workout. Hit every muscle part in your body every session. Concentrate more on the bigger muscles such as chest(Barbell Bench Press), back and(DL) legs(Squat). Use mostly compound exercises. If i;m not mistaken you should be an ecto, mind i suggest u increase ur bfast amount. Ur preworkout does not have enough carbs. Need not concern about the low fat milk, go full cream.

5) As pizzaboy mentioned, it's an obvious symptom of overtrained. I had it before and it;s similar with what u r experiencing. Knowing of what u've been doing at the gym, I would guess that it's a big possibility that u r overtrained. Try not to DL more than once a week and I suspect u might not be taking enough carbs for ur sleeping pleasure. Yes, carbs affect your daily sleeping cycle.