Hi,
First of all, he should still associate nursing with feeding, solids can wait, actually milk should be his main source of food till he is one. AAP recommends now to wait with solids till 6 months so you don't really need to rush with introducing solids at the moment.
If he is impatient with a slow let-down you may want to pump before you nurse him to the point you get your let-down and then put him at the breast. Now, you should be carefull, some babies hit a growth spurt at around his age, my dd had it when she was 5.5 months. This might also be a reason he is screaming because your milk production slowed down due to introducing solids and he actually needs a higher supply.
To increase your supply I recommend that you nurse him for a couple of days instead of offering solids and see how it goes. The nurse at night and then not hungry in the morning is unfortunately also normal though not desirable behaviour. If you want to tackle night wakings, wait till you sort out yoour supply issues/possible growth spurt, OK?