Seeking advice about upgrade vs fitting

Hey everyone, I wanted to come here to see what people think about a dilemma I am currently having. Right now I have two bicycles one is a 2012 Trek 8.2 DS and the other is a 2013 Trek 1.2. Long story short is I stopped riding for a couple years but have recently moved to Madison and have discovered how wonderful cycling is again. So far I have only been riding my 8.2 DS mostly for comfort more than anything else. Well, as a couple months have passed I have started increasing length/elevation of my rides. This is where the 8.2 DS becomes a problem, mainly because of the suspension fork is not very efficient I feel. I have hesitated on pulling out the Trek 1.2 again due to issues I have had in the past with neck pain, hand pain, etc. that I would get on long rides with it. Right now I see myself as having two options and would love any opinions/thoughts on them.

1. Find a new fork to replace the current suspension for on the Trek 8.2 DS and have a shop install it and carry on using that bicycle
or...
2. Go to a local bike shop and receive a professional fitting for the Trek 1.2 and start using that as my main ride hoping any pain/discomforts I have are just fitting issues

Again, any advice I will gladly welcome. Thank you!!