Why does the brush tool come up when I choose the clone stamp?

Could you please post screenshots with the pertinent Panels (Toolbar, Layers, Brushes, Options Bar, …) visible? 

Clone Stamp is using brush to paint pixels. Try to reset tool or simply try to use different brush. You can change brush tip while Clone Stamp is active. With Clone Stamp active right click to bring context menu then select brush. If you have problem with tool switch because preset is saved for some specific tool then Ctrl + Alt + click on brush tip to stay on Clone Stamp and to use desired brush tip.

The preset that you have for your Brush tool should have no effect on the Clone Stamp tool and the brush that it is using. You can:

• Try a different brush for the Clone Stamp tool
  or
• Reset the Clone Stamp tool
  Right-click the tool in the options bar (not Tools panel) and choose Reset

Note: Some brushes have been assigned by the creator to a specific tool. Those brushes have an icon showing the tool.

If this doesn't help, please show a screen shot and ask again.

Jane