It can be played solo aside from the Strongholds (which aren't part of the story). That said, it's fine just playing with randoms. Few things require any communication and coordination.
The story is pretty bland, so it's really only worth it if you enjoy the gameplay. I mean the story is serviceable and some of the dialogue with NPCs and their side stories is alright, but it's not on part with past Bioware games where some would play them just for the story even if the gameplay wasn't great to them. As I said in my prior post, I love flying around and love the combat so I think it's very fun to play and I got my money's worth out of it. I'd definitely suggest giving it a try since you got it for free, and just bailing if you aren't feeling the gameplay after an hour or two.