[Jacqui Holder]

About 90% of the time, when I go to my Texting App or WhatsApp, the Play Store opens automatically. I have cleared the cache repeatedly, turn phone off, back on.... still keeps happening.

[B. Diddy]

Does it open directly to some app page, or does it open to the main Play Store home page? If it opens directly to an app page, then it's likely that it's due to some adware associated with WhatsApp or your other texting app. See what happens if you uninstall apps one by one, starting with WhatsApp.

[Jacqui Holder]

It takes me to a specific app page. This just started recently. I've have the phone, and WhatsApp, for almost 2 months. I used WhatsApp on my old phone and never had a problem. It's not just WhatsApp, it's also happening with the default Texting app (the yellow square icon with the white comment icon inside it - labeled "Messaging").

[B. Diddy]

Regardless of which app it is, it's still likely that some adware has been installed. Start uninstalling apps one by one. Alternatively, you could do a factory reset, then after the Setup Wizard is done, go immediately to the Play Store and stop any app from automatically installing. Then start installing your apps one by one, watching for that behavior to return.