Hi, my baby has problems with her naps too, they are very short but i have notice that if I dedicate some time to wind down like 20 min before the nap its better, to walk with her singing a song, play a little in her room. But it seems your baby may have reflux? My baby is on meds for reflux and she is better. Another option is that he is so tired he cant have a good sleep. Do you have a nice wind down before bed time?, maybe a bath, a lullaby, this can improve his sleep in the night so the day is better for both. I understand, you I've been there, with a lot of crying too, but try to change this little thing first and we will see if it is working. I send you a lot of strength. Do not give up.