Sourdough Starter isnt rising
How exactly are you feeding the starter? Are you just adding new flour and water or are you discarding?

What I do (based on recipes I've seen) is discard 2/3 of the starter and add 1/3 of each new flour and water. So if I have 100g of starter, when I feed it, I discard 67g of it and add 33g of each flour and water.

The reason for this is that it gives the starter a lot more "food". If you start with 50g and add 50g, you've added 100% and then have 100g. If you then add 50g more, you're only adding 50% and have 150g. If you add 50g again, you've only added 33% and have 200g. Because you're adding progressively smaller amounts of food, you will get progressively less activity.

Instead if you discard 1/3 and add 2/3, you'll add 200%, and if you do it again, you'll add another 200%, etc. After a few days of this you should have a very active starter.

This does require discarding some of the starter which is why I keep it relatively small. I use 75g of starter for a loaf of bread, so with 100g I have enough for loaf and then enough to re-make the starter.

The discard can be used in other recipes such as pancakes, banana bread, etc. It is 50/50 flour and water so easy to substitute into other recipes.

Aside from that, you will get more activity at a warmer temperature.  Room temp is usually about 65-70F but the yeast is more active at 85-90F.  But don't go much higher than this or you can make the yeast so active it will produce alcohol or kill it completely.  You can get to this temp a bunch of different ways.  The space above or behind your fridge is often warmer.  If you have an oven with a light, the closed oven with the light on is often warmer.  If you have an aquarium heater those usually hold this temp.  Many electronic devices like computers or wireless access points generate a little bit of heat.

You should not microwave the starter, this will warm it up but you'll probably kill the yeast.  When you are about to feed it you can microwave the water you're using to warm it up first, but don't microwave the starter or flour.

If your water has a lot of chlorine in it, that can inhibit yeast growth. You can either use bottled or filtered water, or leave some water sitting out for a few days to let the chlorine dissipate.