I won't say it's a bad thing to go out by yourself, however if it does make you feel awkward in some situations, I think it might be better to go out with friends some time and just sarge girls when you are with them.
I know a lot of people to go out with, but not everyone is into picking up chicks when they go out. When going out with one of those people I usually just start sarging at the bar. Now you have someone to introduce as well and maybe you can even hook your friend up with a friend of your target!

win/win
Also, when going going out alone, I wouldn't lie about what you are doing. I just wouldn't tell the full truth, just tell people you went out by yourself bc you figured you'd run into people you know anyways. Now you didn't actually lie about what you are doing, they just don't know your intentions. I run into co-workers all the time when going out by myself, I don't really care actually, heck, I'll even have a drink with them! Be social!