sms/imessage entries missing time/date stamp

I just upgraded to IOS7. I could not find a way to show the time/date stamp of a text. This I used quite often... for example, if my husband texts me to say he is on his way home, I could look at the time stamp to see how many minutes ago that was. Is there a way to put the time stamp back on the texts like it was in all the previous versions?

UPDATE: The time/date stamp is there, but the frequency that it puts a new time/date stamp must be fairly long. I had a text started with my husband at 4:55. At 5:32 (looking at the time stamp that shows up on my iMac that shows same texts my iPhone does) another text was made. The only way I can tell when the very absolute LAST text was written on my iPhone is to back out to the menu of all my contact listings I have message conversations with. There it shows when last text was sent... 6:20. That is Almost 50 minutes later than the last text, it is almost an hour and a half since the initial text.But, yet all under same text date stamp of 4:55

EXPLAINED A DIFFERENT WAY:

4:55 first text

5:32 additional text

6:20 next text

Only time stamp shown on my iphone is the 4:55, all these texts are under the same time/date stamp. My iMac mirrors the same texts and shows all three incremental time stamps. That is how my phone used to be. How do I get it back?