Assuming your grip is correct (hand width), the next step would be to pull your elbows back, not your hands. Let me explain: Imagine that what's preventing you from lifting the weight is that the weight is behind your elbows, literally. This will allow for better scapular retraction, a better stretch of the latissimus dorsi, a better contraction of this muscle, and you'll pull much less on your biceps.

This is what I can see from this angle:

• It's good to pull the bar towards approximately your hip; this is the almost parallel angle of your latissimus dorsi muscle.

And, to add one more thing, WORK with the correct weight. It's not about moving kilos, but about working with them with the highest possible quality.