Here are the reasons why Facebook limits some of your account features when you are warned for sending spam. Here is also an article explaining why you are blocked for posting, commenting or sharing on Facebook.
If you think your account is potentially compromised, you can review your activity log by clicking the down arrow at the top right and choosing Settings & Privacy > Activity Log. Check also your recent login history by going here.
In case you don't recognize an activity or if it seems suspicious, secure your account by going to this page.