There is a reason doctors don't give out their personal phone numbers and they don't friend patients on Facebook. Even with the best of intentions, inevitably the patient will make a decision to turn that act of goodwill into an opportunity for free medical care. Happens all the time. If you accede to it just once, it will become a free-for-all event later down the line.
In residency, we had to return phone calls for people who would call the clinic in the middle of the night. Just once, I was so half-asleep that I ended up calling one of my patients back from my own cell phone. For the next three years, I received phone calls, often past midnight, from this patient and friends they had given the number to. Yelling at the patient did no good, they would insist there was an emergency and that I was obligated to help them. It did not matter if I was on-call, on-vacation, or even no longer working at the residency. The calls continued until I moved out of the state and changed my number. I can only imagine what the poor soul who got that number is going through now.
Guy with my old phone number: "I'm telling you, for the fifteenth time, I am not a doctor. Also, it's 3 a.m."
Patient: "Haha, very funny, Dr. Say. So anyway, the kid has this rash on his junk and a bit of a fever at 98.7 degrees...."