is 3 days enough around chicago? im travelling alone. thanks
Depends on what you want to do... what are your plans? What do you want to do/see? More info needed.
Also take a look at the Top Questions on the right hand side of this forum, using the web version (not the phone app). There's lots of info there including a sticky for First Time Visitors, info on where to stay, the airports, etc.
Many travel sites / guidebooks (for example, Lonely Planet, Fodor's, Frommer's) will have sample itineraries of varying length for Chicago, as it is a well known and popular tourist destination. Check those out as well.
Do you want to travel alone though? There is actually a program where you can meet up with a 100% free guide to show you around the city.
If you are staying on a Tuesday, and like art, I think that the Art Institute is free that day. I always find it relaxing.
It could be enough, but it is a decent amount of time.
Some cities have so much to enjoy that you just choose a few on each trip. You can't possibly do everything but it's a nice start. Have a great time!