I have a contract from my boss which he expects me to sign and return. I've had it a couple of weeks and haven't returned it because I've been really busy and because I'm considering trying to renegotiate the compensation.

Here are the details. During my annual review a couple of months ago, I was told I was getting a 5% raise which was higher than most employees received. I was told I am performing really well and to keep it up. I received the contract for this year a couple of weeks ago which is basically the same contract I had the previous year with the compensation updated. However, between the time of the review and now (a period of a couple of months) my job has expanded and I have taken the initiative to take on responsibilities that no one in my department has including my boss. The contract does not indicate any of these are part of my job description though my boss has asked me to take on many of them. These additional responsibilities have helped raise the profile of my department's work in the company among other things.

My concern is if I don't say anything now, I'll keep being offered the standard 2-5% raise and never jump up in pay which I think I deserve. Next year, my boss can just say "keep up the good work" and give me the standard raise. FYI,  I've worked with my boss at several employers and have a good relationship with him.

Should I try to renegotiate the salary? Even if I'm told there's nothing that can be done, I've at least laid the ground work for a bigger raise next year although that might not work out. I don't have another job offer which I am going to work on. My boss has asked me recently if I had another job offer and expressed worry that I did which is one way I know he values me.