Motivation is fleeting as you have now experienced. Motivation will never get you to your goals. Discipline is the real answer. Like others have said, create a routine. Stick to that routine and the benefits of going to the gym will begin to show up in your life. Of course it feels like a chore! Doing dishes is a chore but we all now what happens if you don’t do dishes after a meal; just leads to more work later on. Same thing with fitness.

One of the best things you can do is to build in rest days/times or rewards. Example. Hit the gym for 4 days and reward yourself with a movie with a SO or friend. Don’t hit the 4 days and you have to cancel. That hurts way more than some muscle stiffness the day after the gym.