why is it not going backwards easily

Rear wheel drive vehicles will inherently back up with more ease than going forward if there is a “brake issue” involved - it's pretty simple - you can pull more than you can push - same applies to vehicles .. So we can 'almost' rule out a “brake issue” - but not entirely ... This is more indicative of a transmission malfunction. All that being said - the only way to determine is by *hands-on* evaluation - which will require some familiarity with automobile troubleshooting.