On the deadlift squeeze your chest up hard. Like you are trying to show off your chest to someone in front of you. The idea he is to get the rounding out of your back. I'm thinking there is also a problem in your setup. If you have the starting strength book reread the deadlift chapter and whether you have the book or not watch the starting strength YouTube videos about the deadlift. Hold your back tight throughout the lift squeezing your abs hard as you can.
I've got to go to work but I'll try to remember to come back and say more and talk about your press.