No audio or volume control except on headphones possible cause

Hi, I was handed an iPhone 4S with a very strange issue. There is no audio except for the ringer and phone calls. Eventually y discovered that when you connect it to a dock or cable and disconnect it, it starts to work properly again.

After a while it starts failing again. Headphones work great BTW.

I discovered that the bottom dock connector on the iPhone is somewhat loose because if you insert a plastic pin and try to bend it just a little, It starts working again.

Basically it is like it is always detecting it is connected to a dock speakers or something.

My question to you is. Should this be fixed by replacing the dock connector or the sound system.

I have checked both guides, I just want the opinion of professionals.

Regards,