Heel Injury/Pain

I am hoping someone might be able to help/advise.

About 4 weeks ago i was playing 5 a side football. I felt some pain in my right foot (heel). I can't remember a specific challenge that caused this, if indeed the injury was caused by a challenge. When i got home it really did start to hurt, and the next day was even worse. For the next few days i struggled to put shoes on, walk etc because of the pain.

2 weeks after the injury i thought it was better so i played in an 11 a side game, however i could only last 20 mins due to the injury and wasn't moving freely.

It's been 4 weeks now (since the original injury and 2 weeks since i last played); it's ok now; i can walk with only a slight bit of pain; i took my kid out yesterday and was kicking a ball with him and i could feel the pain coming back.

The pain is coming from the heel; when i squeeze the inside of my heel it is painful. Has anyone had this before? what is the cause? Do i have to rest completely without even light running until it goes away? or can i do a bit of excercise? or does this make it worse? How long does it take to fully recover?

Any advise will be much appreciated. Thanks