Is there any chemical to remove excess solvent that is partly blocking water flow in 3/4 inch PVC pipe ? (the exact location of the restriction/restrictions is not known)
"Shoving " anything solid into a PVC pipe is an almost sure way of breaking it. I have come across a few cases similar and usually found the most economical way is to cut out the area that is blocked and replace with new PVC or PEX. I would recommend this even if it means replacing some wallboard.
No, there is not.
Any chemical that would to that would also dissolve the pipe. Cut back until you find/remove the restriction and then replumb it properly.