Do you by any chance have the Lippert Solara electric awning? There are lots of frustrated people who have the same problem. It is a very poor design. I use shock cords to hold it in position. Two different lengths are attached from the hinged awning supports to small metal loops I installed on the bottom of the awning bracket. I move the shock cords from one end to the other to get the desired pitch. Still not perfect, but better than nothing.
2015 Starcraft Travel Star 299BHU Black Pearl Edition
2011 Jayco X23J (traded in)
2009 Ford F150 FX4 SuperCrew