When paladin spell ranges read 25 + 5ft/2 levels. Does that mean spell levels, or paladin levels. For instance, would a 14th level paladin (casting a 4th level paladin spell) have a range of 35 ft or 60 ft?
It's caster level. For paladins and rangers, caster levels are level-3, so in your example it would be a 50 ft range. (25+ ((11/2)-.5)*5) (that -.5 is to round down since it's an odd level being divided...if it would have been a 13th level paladin it would have just been 10/2 and would still be a range of 50 ft)
...and as a follow up, if the same paladin was to use the UMD feat to activate a shield wand, how would the duration be calculated since it is a 1 min/level spell.
It'd be based on the caster level of the wand. The normal assumption is the caster level is the minimum needed to cast the spell (i.e. CL1 for shield), so 1 minute
If it's not PFS, you can buy higher caster level wands, but just have to pay the higher costs. Wands are (750*spell level*caster level) for a fully charged wand of 50 charges.