You wouldn't run a chkdsk /r on a SSD anyway as it would cause unnecessary wear and is not necessary.
Do you have a Win 7 install disk or USB you can boot up with to navigate to the recovery environment cmd prompt and run the chkdsk /f from there ?
You would first need to enter bcdedit !find "osdevice" to find where it sees the volume, as it doesn't always see it in C: in that mode.
You would then use that partition letter instead of my x and enter the cmd as chkdsk x: /f
For clarity, that's a Pipe symbol before find and is the uppercase of \
TRIM is usually default enabled when you fit a SSD but it's worth checking to see if it is.
http://mywindowshub.com/check-enable-disable-ssd-trim-support-windows-7-windows-8-1/To determine if there's anything wrong with the SSD I would download the 30 day trial version of HD Sentinel.
This will give a written report on its status.
Select the first one under Limited Trial / Free Versions and then uninstall it when done to stop the clock on it where you will be able to run it as and when in future.
https://www.hdsentinel.com/download.php