Do understand that forcing yourself deeper when you have a sinus or ear issue can end tragically. If your body is generating pain, it is telling you to stop the silly thing you are doing. And you should stop, if diving. The really bad part is if it develops into a "Reverse block" which occurs when you cannot clear your airway when ascending instead of descending. From personal experience, that experience is to be avoided.
I am not sure what your dive level is, but I would encourage you to take the Rescue course as soon as you feel comfortable. I feel that all divers should progress to at least rescue level. What you will learn just from self-rescue alone will be worth the course cost.
Plan the dive. Dive the plan. But don't forget to thumb the dive if the plan is impractical or unsafe.
All the best.
S
