mmamprisio

So, I bought my subaru back in January of this year. I bought it with 83k miles on the original motor and trans. I'm currently at 97k. I got my leaking head gasket replaced a month ago and just replaced my dirty air filter. My transmission has been hard shifting ever since October of this year. I changed my transmission fluid not too long ago and it's still pink in color. One of my other problems in my transmission is grinding in gears as well as failure to go into gear. I would put my car into drive and it wouldn't move until I gave it a little gas and it would jolt into gear. Another problem is my car stalling once I make a complete stop. I thought my air filter would of fixed the problem but, it didn't. So, I'm getting anxiety over my transmission problems.
I wish I could figure out what exactly is wrong with my car.
Should I get my codes read?
Or should I just take it to a performance shop?
Or just buy a new trans if that the worst case?