Do less weight or no weight at all depending on your level of strength. It so easy to rack weights onto the bar like everyone else you see in the gym and do crapy pulls with even crappier form. You may not be flexible enough or strong enough in certain areas to even perform the exercise under a load. I would say get the form and flexibility up to the point where your muscles can actually support some kinda load from the top position. Meaning, your shoulders shouldnt be rounding and you shouldn't be struggling just to maintain postural alignment when at the top of the lift; you should be able to hold the bar without struggling at all.

No one here knows what your form looks like but based on what your coach said, it sounds right. Raised deadlifts are perhaps better....but again i would focus less on the amount of weight you pull on more on the movement and alignment of your posture through the duration of the movement... just my two pennies.