Your comments can be your recommendations, your suggestions, your explainations or other comments of your opinion or critique.
Your suggestions can be your recommendations, your other considerations or even your ideas to bring before a person's mind indirectly or without plain expression.
Example: I didn't tell him to leave, I only suggested it.
Your recommendations are not only changes that you mention favorably, but also can be as in being appropriate and / or beneficial.
Example: I recommend the prepackaged sliced lunch meat on sale in the meat dept. more so than the meat to be sliced at the deli for it will last longer.
All recommendations are suggestions, but not all suggestions are recommendations.