2002 Dodge Ram 1500 4.7

I have a 2002 Dodge ram 1500 4.7.  My lower radiator
hose got a gash in it somehow and all of my radiator fluid
drained out. I went ahead and got it fixed and then I had a
check engine light come on took it to get a diagnostics
and they advised me that I had a number seven misfire so
I went and got a new spark plug and fix it Since I just had
a tuneup for five months ago. I still received the check
engine message went and had a diagnostic test it again
and this time it said the same thing  number seven misfire.  
So they advised me to replace the coil and I want to head
and replace the spark plug again. It has been running
rough like it has no power and it just sounds rough it has
been slowly leaking radiator fluid and where it’s going I
have no idea. I just realized that upon start up which has
been getting harder and harder to do light white smoke
came  of the back of the truck.Now today I noticed there
was a light ticking going on and I just feel like my truck is
falling apart and I haveNo idea of what to do it’s still
saying the same thing number seven misfire and now with
all the other fun stuff that it’s doing any information is
great thank you