If you want SMS messages to your phone, it is easily possible.
1) Use ThingHTTP to send an email alert to yourself.
2) In your email service, set up a new filter or rule to forward messages from thingspeak-alerts@mail.thingspeak.com to your phone number.
Here's an example:
1) Attached is my screenshot for the thingHTTP alert I have set up. I first tested this thingHTTP works by making a GET request and confirming the email in my inbox.
2) Since I use Project Fi phone service, I set up a filter in gmail to forward emails from thingspeak-alerts@mail.thingspeak.com to MyPhoneNumber@msg.fi.google.com (See this). If you are using a different cell phone service, this email -> SMS will require using a different address. See this.
