middle finger MCP pain, enlarged

Hi all. I've been having issues with my right hand MCP joint since 5 or 6 months now. It's mostly painful in the morning or after doing heavy activities with it. Some days it's worse, some days better. It got quite a bit worse about 2.5 months ago when there was more of a swelling around the entire MCP. Making a fist around something like holding an umbrella can be painful. Stretching the finger backwards using the extensor is also slightly painful. Pressing on the area that I've marked in the photos below is painful. The entire knuckle seems to be larger than the other hand's middle finger MCP, although it seems it's not so much a swelling as an enlargement of the entire structure (feels quite solid under the skin). I have no history of RA, nor any problems with other joints.

In the period when the pain started to occur it was mostly about being tender to touch but more on the front side of the MCP, right on the area where it is "pointy". At that time I was working a lot on the computer and I operated a mouse with a wheel with the middle finger extensively. I suspect that the initial cause was overuse (RSI). I've tried splinting the middle finger with several splints where I've prevented the MCP from being able to move more or less and join in with forming a full fist. This seemed to help a little at first, but the tenderness remains.

http://i.imgur.com/GazsZGn.jpg
http://i.imgur.com/lNsiJKi.jpg

The MCP of the middle finger is protruding quite a bit higher than with the non-affected hand:

http://i.imgur.com/eCSYO9j.jpg

This is the normal, left hand in comparison:

http://i.imgur.com/UnP12w6.jpg

The splint I've tried for several weeks, but not 100% of the time:

http://i.imgur.com/iVrjMkM.png

No imaging has been done. Can anything be said about this based on this information? I am an IT specialist so I work on the computer all day. I've switch to using a trackpad instead of a mouse most of the time now. However I need to use all fingers for typing. I could possibly schedule to not work for 1 or 2 weeks if needed.

Thanks,

Pete