There is no real 'chords that sound good' together as it all comes down to personal preference of what YOU think sounds good together - unless you go by the cycle of 5ths in which each 7th chord leads onto the next chord but that just gets way too technical.
Bottom line is, you're a beginner, and it's going to take time and practice before you can be happy with stuff you're producing
Keep practicing - often great riffs or chord progressions just come about from simply messing around! Also try and learn as many songs as you can, even if you have to start out with basic ones and work you're way up to more difficult ones - learning other songs sometimes can give you a lot of inspiration. And like AwwSugar said, grab a chord book or, even easier, find a website on the internet where you can learn almost every single chord imaginable. Then you can mess around and experiment with new chords.
A good website for this is:
Guitar Chords