Why am I only getting fluid from the drivers side front caliper?

What is your question?

Just got this van. Decided to change all the brake pads. Noticed that only the front drivers side had fluid coming out and only that same caliper was grabbing. Could the problem be my master cylinder? I kept getting a weird vibration when I stepped on the brakes for a period if time like at a light. This may sound weird but it all seemed to start by changing the bulb in the back passenger side brake light. Spoke to the gentlemen at autozone and they told me that this van might have a bleeder box? I can't seem to find it. I don't have a lot of money to sink into this and I e already spent over $300.