Feels like punching concrete when hitting bag.

Use two kitchen sponges to protect your knuckles or stop using plaster paris with your wraps Margacheeto

 

buy good gloves not the cheapo ****

 

The knuckle problem is par for the course with boxing, this should improve with time. If the knuckle pain is prohibitive, drop the volume of your punchbag workouts for a while and see if that makes a difference.

The wrist issue is of more concern. The first port of call is your wraps - get your trainer to check them.

It could be that your wrists are weak - do you train/stretch your wrists?

Do you have any numbness or tingling sensations in your thumb/fingers, and do you get any of these symptoms when you bend your wrists?

Have you ever been diagnosed with hyperthyroidism?

 

Where exactly in the wrist is the pain, and is it the same in both wrists?

 

Try buying some hand wraps and some quality bag gloves. Don't be punching on the bag bare fisted or only with wraps.:bbb

 

community gloves [the ones everyone uses at the gym] wear down pretty easily.

 

Where exactly in the wrists?

 

Change your wraps, tony.

 

I love hard/heavy bags that actually provide resistance to my punches.

 

Some good points here. Community glove get worn down a lot faster. You need to buy a good pair of glove. Depending on your weight you may need bigger gloves. BTW just cause they are Grant doesn't mean they aren't crap gloves
If you are new to boxing, pain is normal. It can take several months to build strength in you hands and wrists.