Did paul see heaven

The Apostle Paul did see heaven. He documents his experience in 2 Corinthians 12:1-10. In verse two, he states, "I know a man in Christ". He is referring to himself. You can read it for yourself at this link:

2 Corinthians 12: http://www.blueletterbible.org/Bible.cfm?b=2Cr&c=12&t=NKJV

Also, there are commentaries that can help to better understand this passage. If you are interested in other places in The Bible where real people had visions and revelations of heaven, see a list of them in this study guide on 2 Cor 12:

http://www.blueletterbible.org/commentaries/comm_view.cfm?AuthorID=2&contentID=8025&commInfo=31&topic=2%20Corinthians&ar=2Cr_12_2