Trapped. Why can't stock market break out?

Man with computer home
Tetra Images | Getty Images

The S&P 500 has been trapped below the same level after first hitting a record high at the end of February.

Yes, it technically made a new high two weeks ago but then fell back right into the range. Thursday morning it was about a half percent from the record.

Why can't it break out? What's the missing ingredient here?