Is it normal for my rocker arm to do this? I think it’s missing a pin

 

looks like it's missing the LMA, lost motion assembly. it's a spring that goes under the vtec rocker to keep it from flopping around when not in vtec. and you definitely should not be able to lift the rocker up like that with one finger if the LMA was intact

 

is that why i'm getting a p1259 code for vtec system malfunction? I've changed the vtec solenoid, the oil and filter, the oil pressure switch. Its putting me in limp mode at 4k

 

if you have a vtec motor, part of that assembly is for vtec and it's likely it's broke, i would pull another assembly from the junkyard

 

Look for #15{~$10) possibly popped out and is hanging back near the valve springs. It's what keeps the rocker from flopping down. Some aftermarket units replace the hydraulic type plunger with a simple spring.