After you file

The situation you describe seems perfectly normal, and we certainly don't think that you should be especially concerned, in the absence of any additional information or circumstances beyond which you mention in your question.  Please allow us to explain.

While we at TurboTax have no way of finding out specific information about the processing of an individual tax return once it's been transmitted to the government, the activity (and timeframe) you describe gives absolutely no reason to think that you're under review, or that something is wrong with your tax return, so please don't worry or be concerned at this point.

In fact, the messages and bars on the Where's My Refund webpage change all of the time; and sometimes the same message is displayed continuously, or the bars disappear entirely.  If your tax return ever is chosen for further review, or an actual audit, then the website should plainly indicate that, and also let you know to expect an IRS notice or letter by mail.  (You haven't observed any message like that, have you?)

Not all tax returns are identical either, and so they move through the IRS processing system at various speeds.  Thus, one taxpayer's experience may not be reflective or indicative of another taxpayer's experience.

Taxpayers who do have their returns held for review, and who expect to receive an IRS notice, tell us that this message appears clearly on the Where's My Refund website.  The behavior that you observe is more likely an indicator that your tax return is simply moving through the processing system.  It could also be that the IRS is checking for additional information on something related to your tax return (like matching your reported self-employment income data with that separately reported to the IRS by another entity filing Form 1099-MISC); but we wouldn't call that a review . . . perhaps only a small delay.

If enough time passes after filing (21 days after e-file, or 6 weeks after paper file), and there is no new information, at that time the IRS indicates that you can call them, using the phone number provided on their Where's My Refund website.

For now, the best recommended course of action is continued patience.  The IRS doesn't always move as fast as taxpayers would like (especially when waiting for a refund).