Issue with side lamp

Hello,

I am hoping somebody can help ,

Whilst driving to work yesterday I noticed I had a lamp out on drivers side, changed the bulb and worked. thought that was the end of the issue but this morning I have noticed the light is out AGAIN, popped the bonnet had a fiddle with the bulb and worked again, got to my destination and was going back out again and noticed the light is out again.

what could be causing the issue ?

thanks

SJ